diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -4101,6 +4101,14 @@
         return hg.merge(repo, node, force=force, mergeforce=force,
                         labels=labels, abort=abort)
 
+statemod.addunfinished(
+    'merge', fname=None, clearable=True, allowcommit=True,
+    cmdmsg=_('outstanding uncommitted merge'), abortfunc=hg.abortmerge,
+    statushint=_('To continue:    hg commit\n'
+                 'To abort:       hg merge --abort'),
+    cmdhint=_("use 'hg commit' or 'hg merge --abort'")
+)
+
 @command('outgoing|out',
     [('f', 'force', None, _('run even when the destination is unrelated')),
     ('r', 'rev', [],
diff --git a/mercurial/hg.py b/mercurial/hg.py
--- a/mercurial/hg.py
+++ b/mercurial/hg.py
@@ -956,23 +956,11 @@
           abort=False):
     """Branch merge with node, resolving changes. Return true if any
     unresolved conflicts."""
-    if not abort:
-        stats = mergemod.update(repo, node, branchmerge=True, force=force,
-                                mergeforce=mergeforce, labels=labels)
-    else:
-        ms = mergemod.mergestate.read(repo)
-        if ms.active():
-            # there were conflicts
-            node = ms.localctx.hex()
-        else:
-            # there were no conficts, mergestate was not stored
-            node = repo['.'].hex()
-
-        repo.ui.status(_("aborting the merge, updating back to"
-                         " %s\n") % node[:12])
-        stats = mergemod.update(repo, node, branchmerge=False, force=True,
-                                labels=labels)
-
+    if abort:
+        return abortmerge(repo.ui, repo, labels=labels)
+
+    stats = mergemod.update(repo, node, branchmerge=True, force=force,
+                            mergeforce=mergeforce, labels=labels)
     _showstats(repo, stats)
     if stats.unresolvedcount:
         repo.ui.status(_("use 'hg resolve' to retry unresolved file merges "
@@ -981,6 +969,25 @@
         repo.ui.status(_("(branch merge, don't forget to commit)\n"))
     return stats.unresolvedcount > 0
 
+def abortmerge(ui, repo, labels=None, **opts):
+    if opts.get('no_backup'):
+        raise error.Abort(_("merge does not support no-backup flag"))
+    if opts.get('dry_run'):
+        return 0
+    ms = mergemod.mergestate.read(repo)
+    if ms.active():
+        # there were conflicts
+        node = ms.localctx.hex()
+    else:
+        # there were no conficts, mergestate was not stored
+        node = repo['.'].hex()
+
+    repo.ui.status(_("aborting the merge, updating back to"
+                     " %s\n") % node[:12])
+    stats = mergemod.update(repo, node, branchmerge=False, force=True,
+                            labels=labels)
+    _showstats(repo, stats)
+
 def _incoming(displaychlist, subreporecurse, ui, repo, source,
         opts, buffered=False):
     """
diff --git a/mercurial/state.py b/mercurial/state.py
--- a/mercurial/state.py
+++ b/mercurial/state.py
@@ -205,13 +205,6 @@
                  'To mark the changeset bad:     hg bisect --bad\n'
                  'To abort:                      hg bisect --reset\n')
 )
-addunfinished(
-    'merge', fname=None, clearable=True, allowcommit=True,
-    cmdmsg=_('outstanding uncommitted merge'),
-    statushint=_('To continue:    hg commit\n'
-                 'To abort:       hg merge --abort'),
-    cmdhint=_("use 'hg commit' or 'hg merge --abort'")
-)
 
 def getrepostate(repo):
     # experimental config: commands.status.skipstates
diff --git a/tests/test-abort.t b/tests/test-abort.t
--- a/tests/test-abort.t
+++ b/tests/test-abort.t
@@ -661,9 +661,8 @@
 Unshelve abort fails with appropriate message if there's no unshelve in
 progress
   $ hg abort
-  abort: merge does not support 'hg abort'
-  (use 'hg commit' or 'hg merge --abort')
-  [255]
+  aborting the merge, updating back to 9451eaa6eee3
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cd ..
 
 Abort due to pending changes
@@ -976,3 +975,75 @@
   $ hg abort
   abort: no operation in progress
   [255]
+  $ cd ..
+
+####TEST `hg abort` operation merge
+
+  $ addcommit () {
+  >     echo $1 > $1
+  >     hg add $1
+  >     hg commit -d "${2} 0" -m $1
+  > }
+
+  $ commit () {
+  >     hg commit -d "${2} 0" -m $1
+  > }
+
+  $ hg init a
+  $ cd a
+  $ addcommit "A" 0
+  $ addcommit "B" 1
+  $ echo "C" >> A
+  $ commit "C" 2
+
+  $ hg update -C 0
+  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ echo "D" >> A
+  $ commit "D" 3
+  created new head
+
+State before the merge
+
+  $ hg status
+  $ hg id
+  e45016d2b3d3 tip
+  $ hg summary
+  parent: 3:e45016d2b3d3 tip
+   D
+  branch: default
+  commit: (clean)
+  update: 2 new changesets, 2 branch heads (merge)
+  phases: 4 draft
+
+Testing the abort functionality first in case of conflicts
+
+  $ hg abort
+  abort: no operation in progress
+  [255]
+  $ hg merge
+  merging A
+  warning: conflicts while merging A! (edit, then use 'hg resolve --mark')
+  1 files updated, 0 files merged, 0 files removed, 1 files unresolved
+  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
+  [1]
+
+when in dry-run mode
+  $ hg abort --dry-run
+  aborting merge
+
+when in no-backup mode
+  $ hg abort --no-backup
+  abort: merge does not support no-backup flag
+  [255]
+
+when dry-run mode is used with no backup
+  $ hg abort --dry-run --no-backup
+  aborting merge
+  abort: merge does not support no-backup flag
+  [255]
+
+normal abort
+  $ hg abort
+  aborting the merge, updating back to e45016d2b3d3
+  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
+