diff --git a/mypy/errorcodes.py b/mypy/errorcodes.py
index fe460fdec7447..6b63bad72683a 100644
--- a/mypy/errorcodes.py
+++ b/mypy/errorcodes.py
@@ -8,13 +8,10 @@
 from collections import defaultdict
 from typing_extensions import Final
 
-from mypy_extensions import mypyc_attr
-
 error_codes: dict[str, ErrorCode] = {}
 sub_code_map: dict[str, set[str]] = defaultdict(set)
 
 
-@mypyc_attr(serializable=True)
 class ErrorCode:
     def __init__(
         self,