diff --git a/hgext3rd/undo.py b/hgext3rd/undo.py
--- a/hgext3rd/undo.py
+++ b/hgext3rd/undo.py
@@ -334,10 +334,11 @@
 # Undo:
 
 @command('undo', [
-    ('n', 'index', 1, _("how many steps to undo back")),
-    ('f', 'force', False, _("undo across a gap in memory (ADVANCED)")),
     ('a', 'absolute', False, _("absolute based on command index instead of "
                                "relative undo")),
+    ('f', 'force', False, _("undo across a gap in memory (ADVANCED)")),
+    ('k', 'keep', False, _("keep working copy changes")),
+    ('n', 'index', 1, _("how many steps to undo back")),
 ])
 def undo(ui, repo, *args, **opts):
     """ perform an undo
@@ -378,9 +379,22 @@
     repo or another command breaks something.  Undoing across this "gap" can be
     forced, but isn't advised unless its known how the before and after states
     are connected. Undoing up to a gap is safe.
+
+    Use keep to maintain working copy changes.  With keep, undo mimics hg
+    unamend and hg uncommit.  Specifcally, files that exsist currently that
+    don't exsist at the repo state we are undoing to will remain in your
+    workingcopy but not in your changeset.
     """
+    try:
+        extensions.find('inhibit')
+    except KeyError:
+        hint = _("please add inhibit to the list of enabled extensions")
+        e = _("undo requires inhibit extension to be enabled")
+        raise error.Abort(e, hint=hint)
+
     reverseindex = opts.get("index")
     relativeundo = not opts.get("absolute")
+    keep = opts.get("keep")
 
     if repo is not None:
         with repo.wlock(), repo.lock(), repo.transaction("undo"):
@@ -392,7 +406,7 @@
             if not (opts.get("force") or _gapcheck(repo, reverseindex)):
                 raise error.Abort(_("attempted risky undo across"
                                     " missing history"))
-            _undoto(ui, repo, reverseindex)
+            _undoto(ui, repo, reverseindex, keep=keep)
             # store undo data
             # for absolute undos, think of this as a reset
             # for relative undos, think of this as an update
@@ -411,6 +425,13 @@
     and you can use any number of undos/redos up to the current state or back to
     when the undo extension was first active.
     """
+    try:
+        extensions.find('inhibit')
+    except KeyError:
+        hint = _("please add inhibit to the list of enabled extensions")
+        e = _("redo requires inhibit extension to be enabled")
+        raise error.Abort(e, hint=hint)
+
     reverseindex = -1 * abs(opts.get("index"))
     reverseindex = _computerelative(repo, reverseindex)
 
@@ -422,7 +443,7 @@
             _undoto(ui, repo, reverseindex)
             _logundoredoindex(repo, reverseindex)
 
-def _undoto(ui, repo, reverseindex):
+def _undoto(ui, repo, reverseindex, keep=False):
     # undo to specific reverseindex
     try:
         nodedict = _readindex(repo, reverseindex)
@@ -446,8 +467,33 @@
     # working copy parent
     workingcopyparent = _readnode(repo, "workingparent.i",
                                   nodedict["workingparent"])
-    revealcommits(ui, repo, workingcopyparent)
-    commands.update(ui, repo, rev=workingcopyparent)
+    if not keep:
+        revealcommits(ui, repo, workingcopyparent)
+        commands.update(ui, repo, rev=workingcopyparent)
+    else:
+        # keeps working copy files
+        curctx = repo['.']
+        precnode = bin(workingcopyparent)
+        precctx = repo[precnode]
+
+        changedfiles = []
+        wctx = repo[None]
+        wctxmanifest = wctx.manifest()
+        precctxmanifest = precctx.manifest()
+        dirstate = repo.dirstate
+        diff = precctxmanifest.diff(wctxmanifest)
+        changedfiles.extend(diff.iterkeys())
+
+        with dirstate.parentchange():
+            dirstate.rebuild(precnode, precctxmanifest, changedfiles)
+            # we want added and removed files to be shown
+            # properly, not with ? and ! prefixes
+            for filename, data in diff.iteritems():
+                if data[0][0] is None:
+                    dirstate.add(filename)
+                if data[1][0] is None:
+                    dirstate.remove(filename)
+        obsolete.createmarkers(repo, [(curctx, (precctx,))])
 
     # visible changesets
     addedrevs = revsetlang.formatspec('olddraft(0) - olddraft(%d)',
diff --git a/tests/test-undo.t b/tests/test-undo.t
--- a/tests/test-undo.t
+++ b/tests/test-undo.t
@@ -276,3 +276,13 @@
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved
   $ hg undo -a
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+
+hg undo --keep tests
+  $ touch kfl1 && hg add kfl1
+  $ hg st
+  A kfl1
+  $ hg commit --amend
+  $ hg st
+  $ hg undo --keep
+  $ hg st
+  A kfl1