diff --git a/hgext3rd/uncommit.py b/hgext3rd/uncommit.py
--- a/hgext3rd/uncommit.py
+++ b/hgext3rd/uncommit.py
@@ -161,9 +161,13 @@
             if newid is None:
                 raise error.Abort(_('nothing to uncommit'))
 
-            # Move local changes on filtered changeset
-            obsolete.createmarkers(repo, [(old, (repo[newid],))])
-            phases.retractboundary(repo, tr, oldphase, [newid])
+            if newid != old.p1().node():
+                # Move local changes on filtered changeset
+                obsolete.createmarkers(repo, [(old, (repo[newid],))])
+                phases.retractboundary(repo, tr, oldphase, [newid])
+            else:
+                # Fully removed the old commit
+                obsolete.createmarkers(repo, [(old, ())])
 
             with repo.dirstate.parentchange():
                 repo.dirstate.setparents(newid, node.nullid)
diff --git a/tests/test-uncommit.t b/tests/test-uncommit.t
--- a/tests/test-uncommit.t
+++ b/tests/test-uncommit.t
@@ -174,4 +174,29 @@
   |/
   o  0:3004d2d9b50883c1538fc754a3aeb55f1b4084f6 added file-a
   
+Uncommit with draft parent
 
+  $ hg uncommit
+  $ hg phase -r .
+  10: draft
+  $ hg commit -m 'update ab again'
+
+Uncommit with public parent
+
+  $ hg phase -p "::.^"
+  $ hg uncommit
+  $ hg phase -r .
+  10: public
+
+Partial uncommit with public parent
+
+  $ echo xyz > xyz
+  $ hg add xyz
+  $ hg commit -m "update ab and add xyz"
+  $ hg uncommit xyz
+  $ hg status
+  A xyz
+  $ hg phase -r .
+  14: draft
+  $ hg phase -r ".^"
+  10: public