diff --git a/cloud/aws/elasticache/memcached/README.md b/cloud/aws/elasticache/memcached/README.md
index 0c3ae1c..1cf44c2 100644
--- a/cloud/aws/elasticache/memcached/README.md
+++ b/cloud/aws/elasticache/memcached/README.md
@@ -8,8 +8,9 @@ How to use this module
 module "datadog-monitors-aws-elasticcache-redis" {
   source = "git::ssh://git@bitbucket.org/morea/terraform.feature.datadog.git//cloud/aws/elasticache/memcached?ref={revision}"
 
-  message = "${module.datadog-message-alerting.alerting-message}"
-  environment = "${var.environment}"
+  message           = "${module.datadog-message-alerting.alerting-message}"
+  environment       = "${var.environment}"
+  elasticache_size  = "${var.size_of_elsaticache}"
 }
 
 ```
@@ -21,6 +22,7 @@ Creates DataDog monitors with the following checks :
 * Get Hit
 * CPU High
 * Swap
+* Free memory
 
 Inputs
 ------
@@ -34,9 +36,16 @@ Inputs
 | cpu_high_threshold_warning | Elasticache memcached cpu high warning threshold in percentage | string | `75` | no |
 | cpu_high_timeframe | Monitor timeframe for Elasticache memcached cpu high [available values: `last_#m` (1, 5, 10, 15, or 30), `last_#h` (1, 2, or 4), or `last_1d`] | string | `last_15m` | no |
 | delay | Delay in seconds for the metric evaluation | string | `900` | no |
+| elasticache_size | Size of the Elasticache instance | string | - | yes |
 | environment | Architecture Environment | string | - | yes |
 | filter_tags_custom | Tags used for custom filtering when filter_tags_use_defaults is false | string | `*` | no |
 | filter_tags_use_defaults | Use default filter tags convention | string | `true` | no |
+| free_memory_aggregator | Monitor aggregator for Elasticache memcached free memory [available values: min, max, sum or avg] | string | `min` | no |
+| free_memory_message | Custom message for Elasticache memcached free memory monitor | string | `` | no |
+| free_memory_silenced | Groups to mute for Elasticache memcached free memory monitor | map | `<map>` | no |
+| free_memory_threshold_critical | Elasticache memcached free memory critical threshold in percentage | string | `5` | no |
+| free_memory_threshold_warning | Elasticache memcached free memory warning threshold in percentage | string | `10` | no |
+| free_memory_timeframe | Monitor timeframe for Elasticache memcached free memory [available values: `last_#m` (1, 5, 10, 15, or 30), `last_#h` (1, 2, or 4), or `last_1d`] | string | `last_15m` | no |
 | get_hits_aggregator | Monitor aggregator for Elasticache memcached get hits [available values: min, max, sum or avg] | string | `min` | no |
 | get_hits_message | Custom message for Elasticache memcached get hits monitor | string | `` | no |
 | get_hits_silenced | Groups to mute for Elasticache memcached get hits monitor | map | `<map>` | no |
diff --git a/cloud/aws/elasticache/memcached/inputs.tf b/cloud/aws/elasticache/memcached/inputs.tf
index e87d13b..ce8b253 100644
--- a/cloud/aws/elasticache/memcached/inputs.tf
+++ b/cloud/aws/elasticache/memcached/inputs.tf
@@ -24,6 +24,12 @@ variable "filter_tags_custom" {
   default     = "*"
 }
 
+# elasticache variable
+variable "elasticache_size" {
+  description = "Size of the Elasticache instance"
+  type        = "string"
+}
+
 # Memcached specific
 variable "get_hits_silenced" {
   description = "Groups to mute for Elasticache memcached get hits monitor"
@@ -123,3 +129,36 @@ variable "swap_threshold_critical" {
   description = "Elasticache memcached swap critical threshold in percentage"
   default     = 50
 }
+
+variable "free_memory_silenced" {
+  description = "Groups to mute for Elasticache memcached free memory monitor"
+  type        = "map"
+  default     = {}
+}
+
+variable "free_memory_message" {
+  description = "Custom message for Elasticache memcached free memory monitor"
+  type        = "string"
+  default     = ""
+}
+
+variable "free_memory_aggregator" {
+  description = "Monitor aggregator for Elasticache memcached free memory [available values: min, max, sum or avg]"
+  type        = "string"
+  default     = "min"
+}
+
+variable "free_memory_timeframe" {
+  description = "Monitor timeframe for Elasticache memcached free memory [available values: `last_#m` (1, 5, 10, 15, or 30), `last_#h` (1, 2, or 4), or `last_1d`]"
+  default     = "last_15m"
+}
+
+variable "free_memory_threshold_warning" {
+  description = "Elasticache memcached free memory warning threshold in percentage"
+  default     = 10
+}
+
+variable "free_memory_threshold_critical" {
+  description = "Elasticache memcached free memory critical threshold in percentage"
+  default     = 5
+}
diff --git a/cloud/aws/elasticache/memcached/memory.tf b/cloud/aws/elasticache/memcached/memory.tf
new file mode 100644
index 0000000..0d41eeb
--- /dev/null
+++ b/cloud/aws/elasticache/memcached/memory.tf
@@ -0,0 +1,31 @@
+variable "memory" {
+  type = "map"
+
+  description = "Mapping between Elasticache size and Memory."
+
+  default = {
+    cache.t2.micro    = "595926712"
+    cache.t2.small    = "1664299827"
+    cache.t2.medium   = "3457448673"
+    cache.m3.medium   = "2985002270"
+    cache.m3.large    = "6496138035"
+    cache.m3.xlarge   = "14280766259"
+    cache.m3.2xlarge  = "29957396889"
+    cache.m4.large    = "6893422510"
+    cache.m4.xlarge   = "15333033246"
+    cache.m4.2xlarge  = "31890132172"
+    cache.m4.4xlarge  = "65262028062"
+    cache.m4.10xlarge = "166043435663"
+    cache.r3.large    = "14495514624"
+    cache.r3.xlarge   = "30494267801"
+    cache.r3.2xlarge  = "62491774156"
+    cache.r3.4xlarge  = "126701535232"
+    cache.r3.8xlarge  = "254476812288"
+    cache.r4.large    = "13207024435"
+    cache.r4.xlarge   = "26897232691"
+    cache.r4.2xlarge  = "54191749857"
+    cache.r4.4xlarge  = "108855946117"
+    cache.r4.8xlarge  = "218248763146"
+    cache.r4.16xlarge = "437012922368"
+  }
+}
diff --git a/cloud/aws/elasticache/memcached/monitors-memcached.tf b/cloud/aws/elasticache/memcached/monitors-memcached.tf
index 5fa6353..71b83e3 100644
--- a/cloud/aws/elasticache/memcached/monitors-memcached.tf
+++ b/cloud/aws/elasticache/memcached/monitors-memcached.tf
@@ -112,3 +112,36 @@ resource "datadog_monitor" "memcached_swap" {
 
   tags = ["env:${var.environment}", "resource:memcached", "team:aws", "provider:aws"]
 }
+
+resource "datadog_monitor" "memcached_free_memory" {
+  name    = "[${var.environment}] Elasticache memcached free memory {{#is_alert}}{{{comparator}}} {{threshold}}% ({{value}}%){{/is_alert}}{{#is_warning}}{{{comparator}}} {{warn_threshold}}% ({{value}}%){{/is_warning}}"
+  message = "${coalesce(var.free_memory_message, var.message)}"
+
+  type = "metric alert"
+
+  query = <<EOF
+    ${var.free_memory_aggregator}(${var.free_memory_timeframe}): (
+      ${var.free_memory_aggregator}:aws.elasticache.freeable_memory{${data.template_file.filter.rendered}} by {region,cluster,node} /
+      ${var.memory[var.elasticache_size]} * 100
+    ) < ${var.free_memory_threshold_critical}
+  EOF
+
+  thresholds {
+    warning  = "${var.free_memory_threshold_warning}"
+    critical = "${var.free_memory_threshold_critical}"
+  }
+
+  notify_no_data      = true
+  evaluation_delay    = "${var.delay}"
+  renotify_interval   = 0
+  notify_audit        = false
+  timeout_h           = 0
+  include_tags        = true
+  locked              = false
+  require_full_window = false
+  new_host_delay      = "${var.delay}"
+
+  silenced = "${var.free_memory_silenced}"
+
+  tags = ["env:${var.environment}", "resource:memcached", "team:aws", "provider:aws"]
+}
diff --git a/cloud/aws/elasticache/redis/README.md b/cloud/aws/elasticache/redis/README.md
index 736ff08..ab4a06f 100644
--- a/cloud/aws/elasticache/redis/README.md
+++ b/cloud/aws/elasticache/redis/README.md
@@ -8,9 +8,19 @@ How to use this module
 module "datadog-monitors-aws-elasticcache-redis" {
   source = "git::ssh://git@bitbucket.org/morea/terraform.feature.datadog.git//cloud/aws/elasticache/redis?ref={revision}"
 
-  message     = "${module.datadog-message-alerting.alerting-message}"
-  environment = "${var.environment}"
-  redis_size  = "${var.size_of_redis}"
+  message           = "${module.datadog-message-alerting.alerting-message}"
+  environment       = "${var.environment}"
+  elasticache_size  = "${var.size_of_elsaticache}"
+  nodes             = "${data.my_cluster.num_cache_nodes}"
+}
+
+```
+
+You can retrieve the number of nodes using the data source :
+
+```
+data "aws_elasticache_cluster" "my_cluster" {
+  cluster_id = "my-cluster-id"
 }
 
 ```
@@ -24,6 +34,7 @@ Creates DataDog monitors with the following checks:
 * Commands received
 * Replication lag
 * Swap
+* Free memory
 
 Inputs
 ------
@@ -47,11 +58,18 @@ Inputs
 | cpu_high_threshold_warning | Elasticache redis cpu high warning threshold in percentage | string | `75` | no |
 | cpu_high_timeframe | Monitor timeframe for Elasticache redis cpu high [available values: `last_#m` (1, 5, 10, 15, or 30), `last_#h` (1, 2, or 4), or `last_1d`] | string | `last_15m` | no |
 | delay | Delay in seconds for the metric evaluation | string | `900` | no |
+| elasticache_size | Size of the Elasticache instance | string | - | yes |
 | environment | Architecture Environment | string | - | yes |
 | filter_tags_custom | Tags used for custom filtering when filter_tags_use_defaults is false | string | `*` | no |
 | filter_tags_use_defaults | Use default filter tags convention | string | `true` | no |
+| free_memory_aggregator | Monitor aggregator for Elasticache redis free memory [available values: min, max, sum or avg] | string | `min` | no |
+| free_memory_message | Custom message for Elasticache redis free memory monitor | string | `` | no |
+| free_memory_silenced | Groups to mute for Elasticache redis free memory monitor | map | `<map>` | no |
+| free_memory_threshold_critical | Elasticache redis free memory critical threshold in percentage | string | `5` | no |
+| free_memory_threshold_warning | Elasticache redis free memory warning threshold in percentage | string | `10` | no |
+| free_memory_timeframe | Monitor timeframe for Elasticache redis free memory [available values: `last_#m` (1, 5, 10, 15, or 30), `last_#h` (1, 2, or 4), or `last_1d`] | string | `last_15m` | no |
 | message | Message sent when an alert is triggered | string | - | yes |
-| redis_size | Size of the Elasticache redis instance | string | - | yes |
+| nodes | Number of Elasticache nodes | string | - | yes |
 | replication_lag_aggregator | Monitor aggregator for Elasticache redis replication lag [available values: min, max, sum or avg] | string | `min` | no |
 | replication_lag_message | Custom message for Elasticache redis replication lag monitor | string | `` | no |
 | replication_lag_silenced | Groups to mute for Elasticache redis replication lag monitor | map | `<map>` | no |
diff --git a/cloud/aws/elasticache/redis/core.tf b/cloud/aws/elasticache/redis/core.tf
index 988ba69..0970ea6 100644
--- a/cloud/aws/elasticache/redis/core.tf
+++ b/cloud/aws/elasticache/redis/core.tf
@@ -1,7 +1,7 @@
 variable "core" {
   type = "map"
 
-  description = "Mapping between Redis size and vCPU."
+  description = "Mapping between Elasticache size and vCPU."
 
   default = {
     cache.t2.micro    = "1"
diff --git a/cloud/aws/elasticache/redis/inputs.tf b/cloud/aws/elasticache/redis/inputs.tf
index 0b063e4..319d118 100644
--- a/cloud/aws/elasticache/redis/inputs.tf
+++ b/cloud/aws/elasticache/redis/inputs.tf
@@ -24,12 +24,18 @@ variable "filter_tags_custom" {
   default     = "*"
 }
 
-# redis specific
-variable "redis_size" {
-  description = "Size of the Elasticache redis instance"
+# elasticache variable
+variable "elasticache_size" {
+  description = "Size of the Elasticache instance"
   type        = "string"
 }
 
+variable "nodes" {
+  description = "Number of Elasticache nodes"
+  type        = "string"
+}
+
+# redis specific
 variable "cache_hits_silenced" {
   description = "Groups to mute for Elasticache redis cache hits monitor"
   type        = "map"
@@ -174,3 +180,36 @@ variable "commands_timeframe" {
   description = "Monitor timeframe for Elasticache redis commands [available values: `last_#m` (1, 5, 10, 15, or 30), `last_#h` (1, 2, or 4), or `last_1d`]"
   default     = "last_5m"
 }
+
+variable "free_memory_silenced" {
+  description = "Groups to mute for Elasticache redis free memory monitor"
+  type        = "map"
+  default     = {}
+}
+
+variable "free_memory_message" {
+  description = "Custom message for Elasticache redis free memory monitor"
+  type        = "string"
+  default     = ""
+}
+
+variable "free_memory_aggregator" {
+  description = "Monitor aggregator for Elasticache redis free memory [available values: min, max, sum or avg]"
+  type        = "string"
+  default     = "min"
+}
+
+variable "free_memory_timeframe" {
+  description = "Monitor timeframe for Elasticache redis free memory [available values: `last_#m` (1, 5, 10, 15, or 30), `last_#h` (1, 2, or 4), or `last_1d`]"
+  default     = "last_15m"
+}
+
+variable "free_memory_threshold_warning" {
+  description = "Elasticache redis free memory warning threshold in percentage"
+  default     = 10
+}
+
+variable "free_memory_threshold_critical" {
+  description = "Elasticache redis free memory critical threshold in percentage"
+  default     = 5
+}
diff --git a/cloud/aws/elasticache/redis/memory.tf b/cloud/aws/elasticache/redis/memory.tf
new file mode 100644
index 0000000..0d41eeb
--- /dev/null
+++ b/cloud/aws/elasticache/redis/memory.tf
@@ -0,0 +1,31 @@
+variable "memory" {
+  type = "map"
+
+  description = "Mapping between Elasticache size and Memory."
+
+  default = {
+    cache.t2.micro    = "595926712"
+    cache.t2.small    = "1664299827"
+    cache.t2.medium   = "3457448673"
+    cache.m3.medium   = "2985002270"
+    cache.m3.large    = "6496138035"
+    cache.m3.xlarge   = "14280766259"
+    cache.m3.2xlarge  = "29957396889"
+    cache.m4.large    = "6893422510"
+    cache.m4.xlarge   = "15333033246"
+    cache.m4.2xlarge  = "31890132172"
+    cache.m4.4xlarge  = "65262028062"
+    cache.m4.10xlarge = "166043435663"
+    cache.r3.large    = "14495514624"
+    cache.r3.xlarge   = "30494267801"
+    cache.r3.2xlarge  = "62491774156"
+    cache.r3.4xlarge  = "126701535232"
+    cache.r3.8xlarge  = "254476812288"
+    cache.r4.large    = "13207024435"
+    cache.r4.xlarge   = "26897232691"
+    cache.r4.2xlarge  = "54191749857"
+    cache.r4.4xlarge  = "108855946117"
+    cache.r4.8xlarge  = "218248763146"
+    cache.r4.16xlarge = "437012922368"
+  }
+}
diff --git a/cloud/aws/elasticache/redis/monitors-redis.tf b/cloud/aws/elasticache/redis/monitors-redis.tf
index f951958..dd98874 100644
--- a/cloud/aws/elasticache/redis/monitors-redis.tf
+++ b/cloud/aws/elasticache/redis/monitors-redis.tf
@@ -58,7 +58,7 @@ resource "datadog_monitor" "redis_cpu_high" {
   query = <<EOF
     ${var.cpu_high_aggregator}(${var.cpu_high_timeframe}): (
       ${var.cpu_high_aggregator}:aws.elasticache.cpuutilization{${data.template_file.filter.rendered}} by {region,cluster,node}
-    ) > ( ${var.cpu_high_threshold_critical} / ${var.core[var.redis_size]} )
+    ) > ( ${var.cpu_high_threshold_critical} / ${var.core[var.elasticache_size]} )
   EOF
 
   thresholds {
@@ -167,3 +167,36 @@ resource "datadog_monitor" "redis_commands" {
 
   tags = ["env:${var.environment}", "resource:redis", "team:aws", "provider:aws"]
 }
+
+resource "datadog_monitor" "redis_free_memory" {
+  name    = "[${var.environment}] Elasticache redis free memory {{#is_alert}}{{{comparator}}} {{threshold}}% ({{value}}%){{/is_alert}}{{#is_warning}}{{{comparator}}} {{warn_threshold}}% ({{value}}%){{/is_warning}}"
+  message = "${coalesce(var.free_memory_message, var.message)}"
+
+  type = "metric alert"
+
+  query = <<EOF
+    ${var.free_memory_aggregator}(${var.free_memory_timeframe}): (
+      ${var.free_memory_aggregator}:aws.elasticache.freeable_memory{${data.template_file.filter.rendered}} by {region,cluster,node} /
+      ( ${var.memory[var.elasticache_size]} / ${var.nodes} )
+    ) * 100 < ${var.free_memory_threshold_critical}
+  EOF
+
+  thresholds {
+    warning  = "${var.free_memory_threshold_warning}"
+    critical = "${var.free_memory_threshold_critical}"
+  }
+
+  notify_no_data      = true
+  evaluation_delay    = "${var.delay}"
+  renotify_interval   = 0
+  notify_audit        = false
+  timeout_h           = 0
+  include_tags        = true
+  locked              = false
+  require_full_window = false
+  new_host_delay      = "${var.delay}"
+
+  silenced = "${var.free_memory_silenced}"
+
+  tags = ["env:${var.environment}", "resource:redis", "team:aws", "provider:aws"]
+}