diff --git a/specification/cosmos-db/resource-manager/Microsoft.DocumentDB/stable/2015-04-08/cosmos-db.json b/specification/cosmos-db/resource-manager/Microsoft.DocumentDB/stable/2015-04-08/cosmos-db.json
index c8ff3ace7b12..446526c4bb46 100644
--- a/specification/cosmos-db/resource-manager/Microsoft.DocumentDB/stable/2015-04-08/cosmos-db.json
+++ b/specification/cosmos-db/resource-manager/Microsoft.DocumentDB/stable/2015-04-08/cosmos-db.json
@@ -5866,7 +5866,8 @@
       "x-ms-parameter-location": "method",
       "description": "Cosmos DB database account name.",
       "minLength": 3,
-      "maxLength": 50
+      "maxLength": 50,
+      "pattern": "^[a-z0-9]+(-[a-z0-9]+)*"
     },
     "filterParameter": {
       "name": "$filter",