diff --git a/fastapi_crudrouter/core/_utils.py b/fastapi_crudrouter/core/_utils.py
index 4bdfa86..0c997ea 100644
--- a/fastapi_crudrouter/core/_utils.py
+++ b/fastapi_crudrouter/core/_utils.py
@@ -14,7 +14,10 @@ def __init__(self, *args, **kwargs) -> None:  # type: ignore
 
 def get_pk_type(schema: Type[PYDANTIC_SCHEMA], pk_field: str) -> Any:
     try:
-        return schema.__fields__[pk_field].type_
+        if int(pydantic_version.split(".")[0]) >= 2:
+            return schema.model_fields[pk_field].annotation
+        else:
+            return schema.__fields__[pk_field].type_
     except KeyError:
         return int