diff --git a/moto/iam/models.py b/moto/iam/models.py
index a5f40b996..e0f725299 100644
--- a/moto/iam/models.py
+++ b/moto/iam/models.py
@@ -51,8 +51,8 @@ class Policy(BaseModel):
         self.default_version_id = default_version_id or 'v1'
         self.versions = [PolicyVersion(self.arn, document, True)]
 
-        self.create_datetime = datetime.strftime(datetime.utcnow(), "%Y-%m-%dT%H:%M:%SZ")
-        self.update_datetime = datetime.strftime(datetime.utcnow(), "%Y-%m-%dT%H:%M:%SZ")
+        self.create_datetime = datetime.now(pytz.utc)
+        self.update_datetime = datetime.now(pytz.utc)
 
 
 class SAMLProvider(BaseModel):
@@ -76,7 +76,7 @@ class PolicyVersion(object):
         self.is_default = is_default
         self.version_id = 'v1'
 
-        self.create_datetime = datetime.strftime(datetime.utcnow(), "%Y-%m-%dT%H:%M:%SZ")
+        self.create_datetime = datetime.now(pytz.utc)
 
 
 class ManagedPolicy(Policy):
@@ -132,7 +132,7 @@ class Role(BaseModel):
         self.path = path or '/'
         self.policies = {}
         self.managed_policies = {}
-        self.create_date = datetime.strftime(datetime.utcnow(), "%Y-%m-%dT%H:%M:%SZ")
+        self.create_date = datetime.now(pytz.utc)
         self.tags = {}
         self.description = ""
 
diff --git a/moto/iam/responses.py b/moto/iam/responses.py
index c981f9b35..5be07430f 100644
--- a/moto/iam/responses.py
+++ b/moto/iam/responses.py
@@ -742,12 +742,12 @@ CREATE_POLICY_TEMPLATE = """<CreatePolicyResponse>
     <Policy>
       <Arn>{{ policy.arn }}</Arn>
       <AttachmentCount>{{ policy.attachment_count }}</AttachmentCount>
-      <CreateDate>{{ policy.create_datetime }}</CreateDate>
+      <CreateDate>{{ policy.create_datetime.isoformat() }}</CreateDate>
       <DefaultVersionId>{{ policy.default_version_id }}</DefaultVersionId>
       <Path>{{ policy.path }}</Path>
       <PolicyId>{{ policy.id }}</PolicyId>
       <PolicyName>{{ policy.name }}</PolicyName>
-      <UpdateDate>{{ policy.update_datetime }}</UpdateDate>
+      <UpdateDate>{{ policy.update_datetime.isoformat() }}</UpdateDate>
     </Policy>
   </CreatePolicyResult>
   <ResponseMetadata>
@@ -765,8 +765,8 @@ GET_POLICY_TEMPLATE = """<GetPolicyResponse>
       <Path>{{ policy.path }}</Path>
       <Arn>{{ policy.arn }}</Arn>
       <AttachmentCount>{{ policy.attachment_count }}</AttachmentCount>
-      <CreateDate>{{ policy.create_datetime }}</CreateDate>
-      <UpdateDate>{{ policy.update_datetime }}</UpdateDate>
+      <CreateDate>{{ policy.create_datetime.isoformat() }}</CreateDate>
+      <UpdateDate>{{ policy.update_datetime.isoformat() }}</UpdateDate>
     </Policy>
   </GetPolicyResult>
   <ResponseMetadata>
@@ -858,7 +858,7 @@ LIST_POLICIES_TEMPLATE = """<ListPoliciesResponse>
         <Path>{{ policy.path }}</Path>
         <PolicyId>{{ policy.id }}</PolicyId>
         <PolicyName>{{ policy.name }}</PolicyName>
-        <UpdateDate>{{ policy.update_datetime.isoformat() }}</UpdateDate>
+        <UpdateDate>{{ policy.update_datetime }}</UpdateDate>
       </member>
       {% endfor %}
     </Policies>
@@ -951,7 +951,7 @@ UPDATE_ROLE_DESCRIPTION_TEMPLATE = """<UpdateRoleDescriptionResponse xmlns="http
       <Arn>{{ role.arn }}</Arn>
       <RoleName>{{ role.name }}</RoleName>
       <AssumeRolePolicyDocument>{{ role.assume_role_policy_document }}</AssumeRolePolicyDocument>
-      <CreateDate>{{ role.create_date }}</CreateDate>
+      <CreateDate>{{ role.create_date.isoformat() }}</CreateDate>
       <RoleId>{{ role.id }}</RoleId>
       {% if role.tags %}
       <Tags>
diff --git a/tests/test_iam/test_iam.py b/tests/test_iam/test_iam.py
index 80a7fe99e..85c51012f 100644
--- a/tests/test_iam/test_iam.py
+++ b/tests/test_iam/test_iam.py
@@ -1161,7 +1161,6 @@ def test_update_role_description():
         conn.delete_role(RoleName="my-role")
 
     conn.create_role(RoleName="my-role", AssumeRolePolicyDocument="some policy", Path="/my-path/")
-    role = conn.get_role(RoleName="my-role")
     response = conn.update_role_description(RoleName="my-role", Description="test")
 
     assert response['Role']['RoleName'] == 'my-role'
@@ -1174,7 +1173,6 @@ def test_update_role():
         conn.delete_role(RoleName="my-role")
 
     conn.create_role(RoleName="my-role", AssumeRolePolicyDocument="some policy", Path="/my-path/")
-    role = conn.get_role(RoleName="my-role")
     response = conn.update_role_description(RoleName="my-role", Description="test")
 
-    assert response['Role']['RoleName'] == 'my-role'
\ No newline at end of file
+    assert response['Role']['RoleName'] == 'my-role'