diff --git a/stdlib/3.4/enum.pyi b/stdlib/3.4/enum.pyi
index 271126006..09b3d8aa6 100644
--- a/stdlib/3.4/enum.pyi
+++ b/stdlib/3.4/enum.pyi
@@ -11,13 +11,14 @@ _S = TypeVar('_S', bound=Type[Enum])
 # such as str as mixins, which due to the handling of ABCs of builtin types, cause
 # spurious inconsistent metaclass structure. See #1595.
 # Structurally: Iterable[T], Reversible[T], Container[T] where T is the enum itself
-class EnumMeta(ABCMeta, Sized):
+class EnumMeta(ABCMeta):
     def __iter__(self: Type[_T]) -> Iterator[_T]: ...
     def __reversed__(self: Type[_T]) -> Iterator[_T]: ...
     def __contains__(self: Type[_T], member: Any) -> bool: ...
     def __getitem__(self: Type[_T], name: str) -> _T: ...
     @property
     def __members__(self: Type[_T]) -> Mapping[str, _T]: ...
+    def __len__(self) -> int: ...
 
 class Enum(metaclass=EnumMeta):
     def __new__(cls: Type[_T], value: Any) -> _T: ...