diff --git a/moto/ec2/models.py b/moto/ec2/models.py
index a7c0133c7..0a2c3ffb7 100644
--- a/moto/ec2/models.py
+++ b/moto/ec2/models.py
@@ -98,7 +98,7 @@ from .utils import (
 
 
 def utc_date_and_time():
-    return datetime.utcnow().strftime('%Y-%m-%dT%H:%M:%SZ')
+    return datetime.utcnow().strftime('%Y-%m-%dT%H:%M:%S.000Z')
 
 
 def validate_resource_ids(resource_ids):
diff --git a/tests/test_ec2/test_instances.py b/tests/test_ec2/test_instances.py
index 629fc67ee..2e9b9834a 100644
--- a/tests/test_ec2/test_instances.py
+++ b/tests/test_ec2/test_instances.py
@@ -53,7 +53,7 @@ def test_instance_launch_and_terminate():
     instances.should.have.length_of(1)
     instances[0].id.should.equal(instance.id)
     instances[0].state.should.equal('running')
-    instances[0].launch_time.should.equal("2014-01-01T05:00:00Z")
+    instances[0].launch_time.should.equal("2014-01-01T05:00:00.000Z")
     instances[0].vpc_id.should.equal(None)
 
     root_device_name = instances[0].root_device_name