diff --git a/pandas/core/internals/managers.py b/pandas/core/internals/managers.py
index 2f1206e800d9b..08131a977bda3 100644
--- a/pandas/core/internals/managers.py
+++ b/pandas/core/internals/managers.py
@@ -781,9 +781,6 @@ def get_slice(self, slobj: slice, axis: int = 0) -> "BlockManager":
         bm = type(self)(new_blocks, new_axes, do_integrity_check=False)
         return bm
 
-    def __contains__(self, item) -> bool:
-        return item in self.items
-
     @property
     def nblocks(self) -> int:
         return len(self.blocks)
diff --git a/pandas/tests/internals/test_internals.py b/pandas/tests/internals/test_internals.py
index 657849874f091..57fbc9ab13f84 100644
--- a/pandas/tests/internals/test_internals.py
+++ b/pandas/tests/internals/test_internals.py
@@ -301,10 +301,6 @@ def test_duplicate_ref_loc_failure(self):
         mgr = BlockManager(blocks, axes)
         mgr.iget(1)
 
-    def test_contains(self, mgr):
-        assert "a" in mgr
-        assert "baz" not in mgr
-
     def test_pickle(self, mgr):
 
         mgr2 = tm.round_trip_pickle(mgr)