diff --git a/CHANGELOG.md b/CHANGELOG.md
index e0f0afaabed..8e6a8904bf2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -45,6 +45,9 @@ Updates:
 - Resource SDK: Reverse (suggested) order of Resource.Merge parameters, remove
   special case for empty strings
   ([#1345](https://github.com/open-telemetry/opentelemetry-specification/pull/1345))
+- Resource attributes: lowerecased the allowed values of the `aws.ecs.launchtype`
+  attribute
+  ([#1339](https://github.com/open-telemetry/opentelemetry-specification/pull/1339))
 - Trace Exporters: Fix TODOs in Jaeger exporter spec
   ([#1374](https://github.com/open-telemetry/opentelemetry-specification/pull/1374))
 
diff --git a/semantic_conventions/resource/cloud_provider/aws/ecs.yaml b/semantic_conventions/resource/cloud_provider/aws/ecs.yaml
index 543639c4c81..3c8b0d72268 100644
--- a/semantic_conventions/resource/cloud_provider/aws/ecs.yaml
+++ b/semantic_conventions/resource/cloud_provider/aws/ecs.yaml
@@ -19,12 +19,12 @@ groups:
           allow_custom_values: false
           members:
             - id: ec2
-              value: "EC2"
+              value: "ec2"
             - id: fargate
-              value: "Fargate"
+              value: "fargate"
         brief: >
           The [launch type](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/launch_types.html) for an ECS task.
-        examples: ['EC2', 'Fargate']
+        examples: ['ec2', 'fargate']
       - id: task.arn
         type: string
         brief: >
diff --git a/specification/resource/semantic_conventions/cloud_provider/aws/ecs.md b/specification/resource/semantic_conventions/cloud_provider/aws/ecs.md
index 57985a6c135..1b6cd220344 100644
--- a/specification/resource/semantic_conventions/cloud_provider/aws/ecs.md
+++ b/specification/resource/semantic_conventions/cloud_provider/aws/ecs.md
@@ -9,7 +9,7 @@
 |---|---|---|---|---|
 | `aws.ecs.container.arn` | string | The Amazon Resource Name (ARN) of an [ECS container instance](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/ECS_instances.html). | `arn:aws:ecs:us-west-1:123456789123:container/32624152-9086-4f0e-acae-1a75b14fe4d9` | No |
 | `aws.ecs.cluster.arn` | string | The ARN of an [ECS cluster](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/clusters.html). | `arn:aws:ecs:us-west-2:123456789123:cluster/my-cluster` | No |
-| `aws.ecs.launchtype` | string | The [launch type](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/launch_types.html) for an ECS task. | `EC2`; `Fargate` | No |
+| `aws.ecs.launchtype` | string | The [launch type](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/launch_types.html) for an ECS task. | `ec2`; `fargate` | No |
 | `aws.ecs.task.arn` | string | The ARN of an [ECS task definition](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task_definitions.html). | `arn:aws:ecs:us-west-1:123456789123:task/10838bed-421f-43ef-870a-f43feacbbb5b` | No |
 | `aws.ecs.task.family` | string | The task definition family this task definition is a member of. | `opentelemetry-family` | No |
 
@@ -17,6 +17,6 @@
 
 | Value  | Description |
 |---|---|
-| `EC2` | ec2 |
-| `Fargate` | fargate |
+| `ec2` | ec2 |
+| `fargate` | fargate |
 <!-- endsemconv -->