diff --git a/doc/source/whatsnew/v0.23.0.txt b/doc/source/whatsnew/v0.23.0.txt
index c194d98a89789..3320bd224d5fb 100644
--- a/doc/source/whatsnew/v0.23.0.txt
+++ b/doc/source/whatsnew/v0.23.0.txt
@@ -1019,6 +1019,7 @@ Removal of prior version deprecations/changes
   ``ambiguous='infer'``, and ``infer_dst=False`` to ``ambiguous='raise'`` (:issue:`7963`).
 - When ``.resample()`` was changed from an eager to a lazy operation, like ``.groupby()`` in v0.18.0, we put in place compatibility (with a ``FutureWarning``),
   so operations would continue to work. This is now fully removed, so a ``Resampler`` will no longer forward compat operations (:issue:`20554`)
+- Remove long deprecated ``axis=None`` parameter from ``.replace()`` (:issue:`20271`)
 
 .. _whatsnew_0230.performance:
 
diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 83d6dee64c165..7a2bd2708b711 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -3790,11 +3790,11 @@ def fillna(self, value=None, method=None, axis=None, inplace=False,
 
     @Appender(_shared_docs['replace'] % _shared_doc_kwargs)
     def replace(self, to_replace=None, value=None, inplace=False, limit=None,
-                regex=False, method='pad', axis=None):
+                regex=False, method='pad'):
         return super(DataFrame, self).replace(to_replace=to_replace,
                                               value=value, inplace=inplace,
                                               limit=limit, regex=regex,
-                                              method=method, axis=axis)
+                                              method=method)
 
     @Appender(_shared_docs['shift'] % _shared_doc_kwargs)
     def shift(self, periods=1, freq=None, axis=0):
diff --git a/pandas/core/series.py b/pandas/core/series.py
index 2bf96ddaedf6f..951227f381b1c 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -3423,11 +3423,10 @@ def fillna(self, value=None, method=None, axis=None, inplace=False,
 
     @Appender(generic._shared_docs['replace'] % _shared_doc_kwargs)
     def replace(self, to_replace=None, value=None, inplace=False, limit=None,
-                regex=False, method='pad', axis=None):
+                regex=False, method='pad'):
         return super(Series, self).replace(to_replace=to_replace, value=value,
                                            inplace=inplace, limit=limit,
-                                           regex=regex, method=method,
-                                           axis=axis)
+                                           regex=regex, method=method)
 
     @Appender(generic._shared_docs['shift'] % _shared_doc_kwargs)
     def shift(self, periods=1, freq=None, axis=0):