diff --git a/changes/3697.feature.md b/changes/3697.feature.md
new file mode 100644
index 00000000000..6d16f4b5514
--- /dev/null
+++ b/changes/3697.feature.md
@@ -0,0 +1 @@
+Handle `None` arguments properly in `ContainerRegistryNode` GQL API.
diff --git a/src/ai/backend/manager/models/gql_models/container_registry.py b/src/ai/backend/manager/models/gql_models/container_registry.py
index fabda6098de..7b0d3c77dd4 100644
--- a/src/ai/backend/manager/models/gql_models/container_registry.py
+++ b/src/ai/backend/manager/models/gql_models/container_registry.py
@@ -331,12 +331,12 @@ async def mutate(
         url: str,
         type: ContainerRegistryType,
         registry_name: str,
-        is_global: bool | UndefinedType = Undefined,
-        project: str | UndefinedType = Undefined,
-        username: str | UndefinedType = Undefined,
-        password: str | UndefinedType = Undefined,
-        ssl_verify: bool | UndefinedType = Undefined,
-        extra: dict | UndefinedType = Undefined,
+        is_global: bool | UndefinedType | None = Undefined,
+        project: str | UndefinedType | None = Undefined,
+        username: str | UndefinedType | None = Undefined,
+        password: str | UndefinedType | None = Undefined,
+        ssl_verify: bool | UndefinedType | None = Undefined,
+        extra: dict | UndefinedType | None = Undefined,
     ) -> CreateContainerRegistryNode:
         ctx: GraphQueryContext = info.context
 
@@ -347,7 +347,7 @@ async def mutate(
         }
 
         def _set_if_set(name: str, val: Any) -> None:
-            if val is not Undefined:
+            if val is not Undefined and val is not None:
                 input_config[name] = val
 
         _set_if_set("project", project)
@@ -402,22 +402,22 @@ async def mutate(
         root,
         info: graphene.ResolveInfo,
         id: str,
-        url: str | UndefinedType = Undefined,
-        type: ContainerRegistryType | UndefinedType = Undefined,
-        registry_name: str | UndefinedType = Undefined,
-        is_global: bool | UndefinedType = Undefined,
-        project: str | UndefinedType = Undefined,
-        username: str | UndefinedType = Undefined,
-        password: str | UndefinedType = Undefined,
-        ssl_verify: bool | UndefinedType = Undefined,
-        extra: dict | UndefinedType = Undefined,
+        url: str | UndefinedType | None = Undefined,
+        type: ContainerRegistryType | UndefinedType | None = Undefined,
+        registry_name: str | UndefinedType | None = Undefined,
+        is_global: bool | UndefinedType | None = Undefined,
+        project: str | UndefinedType | None = Undefined,
+        username: str | UndefinedType | None = Undefined,
+        password: str | UndefinedType | None = Undefined,
+        ssl_verify: bool | UndefinedType | None = Undefined,
+        extra: dict | UndefinedType | None = Undefined,
     ) -> ModifyContainerRegistryNode:
         ctx: GraphQueryContext = info.context
 
         input_config: dict[str, Any] = {}
 
         def _set_if_set(name: str, val: Any) -> None:
-            if val is not Undefined:
+            if val is not Undefined and val is not None:
                 input_config[name] = val
 
         _set_if_set("url", url)
diff --git a/src/ai/backend/manager/models/gql_models/container_registry_v2.py b/src/ai/backend/manager/models/gql_models/container_registry_v2.py
index 26e4f868b91..b29560ba56a 100644
--- a/src/ai/backend/manager/models/gql_models/container_registry_v2.py
+++ b/src/ai/backend/manager/models/gql_models/container_registry_v2.py
@@ -77,7 +77,7 @@ async def mutate(
         }
 
         def _set_if_set(name: str, val: Any) -> None:
-            if val is not Undefined:
+            if val is not Undefined and val is not None:
                 input_config[name] = val
 
         _set_if_set("project", props.project)
@@ -149,7 +149,7 @@ async def mutate(
         input_config: dict[str, Any] = {}
 
         def _set_if_set(name: str, val: Any) -> None:
-            if val is not Undefined:
+            if val is not Undefined and val is not None:
                 input_config[name] = val
 
         _set_if_set("url", props.url)