diff --git a/src/azure-cli/azure/cli/command_modules/backup/custom_base.py b/src/azure-cli/azure/cli/command_modules/backup/custom_base.py
index cec78d8808b..f51497cb2c9 100644
--- a/src/azure-cli/azure/cli/command_modules/backup/custom_base.py
+++ b/src/azure-cli/azure/cli/command_modules/backup/custom_base.py
@@ -3,6 +3,7 @@
 # Licensed under the MIT License. See License.txt in the project root for license information.
 # --------------------------------------------------------------------------------------------
 
+from datetime import datetime, timezone, timedelta
 import azure.cli.command_modules.backup.custom as custom
 import azure.cli.command_modules.backup.custom_afs as custom_afs
 import azure.cli.command_modules.backup.custom_help as custom_help
@@ -100,6 +101,9 @@ def backup_now(cmd, client, resource_group_name, vault_name, item_name, retain_u
     if isinstance(item, list):
         raise ValidationError("Multiple items found. Please give native names instead.")
 
+    if retain_until is None:
+        retain_until = datetime.now(timezone.utc) + timedelta(days=30)
+
     if item.properties.backup_management_type.lower() == "azureiaasvm":
         return custom.backup_now(cmd, client, resource_group_name, vault_name, item, retain_until)