diff --git a/nodepool/driver/aws/adapter.py b/nodepool/driver/aws/adapter.py
index e8f6dde00..d670950b5 100644
--- a/nodepool/driver/aws/adapter.py
+++ b/nodepool/driver/aws/adapter.py
@@ -1709,7 +1709,9 @@ class AwsAdapter(statemachine.Adapter):
                 }
 
             if label.userdata:
-                template_data['UserData'] = label.userdata
+                userdata_base64 = base64.b64encode(
+                    label.userdata.encode('ascii')).decode('utf-8')
+                template_data['UserData'] = userdata_base64
 
             template_args = dict(
                 LaunchTemplateData=template_data,
diff --git a/nodepool/tests/unit/test_driver_aws.py b/nodepool/tests/unit/test_driver_aws.py
index a74fa2372..794f18a82 100644
--- a/nodepool/tests/unit/test_driver_aws.py
+++ b/nodepool/tests/unit/test_driver_aws.py
@@ -1444,7 +1444,8 @@ class TestDriverAws(tests.DBTestCase):
                 LaunchTemplateId=lt1['LaunchTemplateId'])[
                     'LaunchTemplateVersions'][0]
         lt1_data = lt1_version['LaunchTemplateData']
-        self.assertEqual(lt1_data['UserData'], 'some-command')
+        lt1_userdata = base64.b64decode(lt1_data['UserData']).decode()
+        self.assertEqual(lt1_userdata, 'some-command')
 
         # Get details from second launch template
         lt2_version = self.ec2_client.\