diff --git a/pandas/core/algorithms.py b/pandas/core/algorithms.py
index e6847b380a7e8..7fc391d3ffb51 100644
--- a/pandas/core/algorithms.py
+++ b/pandas/core/algorithms.py
@@ -47,6 +47,7 @@
     is_bool_dtype,
     is_complex_dtype,
     is_dict_like,
+    is_dtype_equal,
     is_extension_array_dtype,
     is_float,
     is_float_dtype,
@@ -511,6 +512,7 @@ def isin(comps: ListLike, values: ListLike) -> npt.NDArray[np.bool_]:
             len(values) > 0
             and values.dtype.kind in "iufcb"
             and not is_signed_integer_dtype(comps)
+            and not is_dtype_equal(values, comps)
         ):
             # GH#46485 Use object to avoid upcast to float64 later
             # TODO: Share with _find_common_type_compat