diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -598,6 +598,8 @@ def backout(ui, repo, node=None, rev=Non
 def _dobackout(ui, repo, node=None, rev=None, **opts):
     if opts.get('commit') and opts.get('no_commit'):
         raise error.Abort(_("cannot use --commit with --no-commit"))
+    if opts.get('merge') and opts.get('no_commit'):
+        raise error.Abort(_("cannot use --merge with --no-commit"))
 
     if rev and node:
         raise error.Abort(_("please specify just one revision"))
diff --git a/tests/test-backout.t b/tests/test-backout.t
--- a/tests/test-backout.t
+++ b/tests/test-backout.t
@@ -753,3 +753,10 @@ Test usage of `hg resolve` in case of co
   $ hg backout --no-commit .
   removing 3
   changeset cccc23d9d68f backed out, don't forget to commit.
+  $ hg revert -aq
+
+--no-commit can't be used with --merge
+
+  $ hg backout --merge --no-commit 2
+  abort: cannot use --merge with --no-commit
+  [255]