diff --git a/changelogs/fragments/1627-ssm_parameter-KeyError-when-adding-description.yml b/changelogs/fragments/1627-ssm_parameter-KeyError-when-adding-description.yml
new file mode 100644
index 00000000000..98344a6ff4a
--- /dev/null
+++ b/changelogs/fragments/1627-ssm_parameter-KeyError-when-adding-description.yml
@@ -0,0 +1,2 @@
+bugfixes:
+  - ssm_parameter - Fix a ``KeyError`` when adding a description to an existing parameter (https://github.com/ansible-collections/community.aws/issues/1471).
diff --git a/plugins/modules/ssm_parameter.py b/plugins/modules/ssm_parameter.py
index af4de1c15fb..5381c0d67bf 100644
--- a/plugins/modules/ssm_parameter.py
+++ b/plugins/modules/ssm_parameter.py
@@ -383,7 +383,7 @@ def create_update_parameter(client, module):
                 except (botocore.exceptions.ClientError, botocore.exceptions.BotoCoreError) as e:
                     module.fail_json_aws(e, msg="getting description value")
 
-                if describe_existing_parameter['Description'] != args['Description']:
+                if describe_existing_parameter.get('Description') != args['Description']:
                     (changed, response) = update_parameter(client, module, **args)
         if changed:
             _wait_updated(client, module, module.params.get('name'), original_version)
diff --git a/tests/integration/targets/ssm_parameter/tasks/main.yml b/tests/integration/targets/ssm_parameter/tasks/main.yml
index 7f4e4f6e2d4..3d4fb643b30 100644
--- a/tests/integration/targets/ssm_parameter/tasks/main.yml
+++ b/tests/integration/targets/ssm_parameter/tasks/main.yml
@@ -415,6 +415,30 @@
       that:
       - result is not changed
 
+  - name: Create key/value pair in aws parameter store with no description
+    aws_ssm_parameter_store:
+      name: '{{ simple_name }}'
+      value: '{{ simple_value }}'
+    register: result
+
+  - assert:
+      that:
+      - result is changed
+      - '"description" not in result.parameter_metadata'
+
+  - name: Add a description
+    aws_ssm_parameter_store:
+      name: '{{ simple_name }}'
+      value: '{{ simple_value }}'
+      description: '{{ simple_description }}'
+    register: result
+
+  - assert:
+      that:
+        - result is changed
+        - '"description" in result.parameter_metadata'
+        - result.parameter_metadata.description == simple_description
+
   always:
   # ============================================================
   - name: Delete remaining key/value pairs in aws parameter store