diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -7590,6 +7590,7 @@
 @command(
     b'update|up|checkout|co',
     [
+        (b'a', b'abort', None, _(b'abort the interrupted update')),
         (b'C', b'clean', None, _(b'discard uncommitted changes (no backup)')),
         (b'c', b'check', None, _(b'require clean working directory')),
         (b'm', b'merge', None, _(b'merge uncommitted changes')),
@@ -7661,9 +7662,26 @@
     clean = opts.get('clean')
     check = opts.get('check')
     merge = opts.get('merge')
+    abort = opts.get('abort')
     if rev and node:
         raise error.Abort(_(b"please specify just one revision"))
 
+    if abort:
+        overrides = {(b'ui', b'forcemerge'): b':local', (b'ui', 'quiet'): True}
+        with repo.wlock(), ui.configoverride(overrides, b'update'):
+            ms = mergemod.mergestate.read(repo)
+            if not ms.active():
+                raise error.Abort(_(b'no interrupted update exists'))
+            resolve(ui, repo, **{'unmark': True})
+            resolve(ui, repo, **{'all': True, 'tool':':local'})
+            # hg update to orig revision
+            local = ms.localctx
+            updatecheck = b'none'
+            hg.updatetotally(ui, repo, local, local, updatecheck=updatecheck)
+            ms.clean(repo)
+        ui.status(_(b'update aborted\n'))
+        return 0
+
     if ui.configbool(b'commands', b'update.requiredest'):
         if not node and not rev and not date:
             raise error.Abort(
diff --git a/tests/test-completion.t b/tests/test-completion.t
--- a/tests/test-completion.t
+++ b/tests/test-completion.t
@@ -357,7 +357,7 @@
   tip: patch, git, style, template
   unbundle: update
   unshelve: abort, continue, interactive, keep, name, tool, date
-  update: clean, check, merge, date, rev, tool
+  update: abort, clean, check, merge, date, rev, tool
   verify: full
   version: template
 
diff --git a/tests/test-update-branches.t b/tests/test-update-branches.t
--- a/tests/test-update-branches.t
+++ b/tests/test-update-branches.t
@@ -676,3 +676,80 @@
   [255]
   $ hg co --no-check 2
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+
+  $ cd ..
+
+Test hg update --abort option
+  $ hg init issue4404
+  $ cd issue4404
+  $ echo "before\nmiddle" > file
+  $ hg add file
+  $ hg commit -mbefore
+  $ echo "after\nmiddle" > file
+  $ hg commit -mafter
+  $ echo "edited\nmiddle\nlast" > file
+  $ echo foo > foo
+  $ hg add foo
+
+  $ hg diff
+  diff -r fd93e7c2e3ea file
+  --- a/file	Thu Jan 01 00:00:00 1970 +0000
+  +++ b/file	Thu Jan 01 00:00:00 1970 +0000
+  @@ -1,2 +1,3 @@
+  -after
+  +edited
+   middle
+  +last
+  diff -r fd93e7c2e3ea foo
+  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+  +++ b/foo	Thu Jan 01 00:00:00 1970 +0000
+  @@ -0,0 +1,1 @@
+  +foo
+
+  $ hg update 0 --no-check
+  merging file
+  warning: conflicts while merging file! (edit, then use 'hg resolve --mark')
+  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
+  use 'hg resolve' to retry unresolved file merges
+  [1]
+  $ hg diff
+  diff -r f013c8cc5b24 file
+  --- a/file	Thu Jan 01 00:00:00 1970 +0000
+  +++ b/file	Thu Jan 01 00:00:00 1970 +0000
+  @@ -1,2 +1,7 @@
+  +<<<<<<< working copy: fd93e7c2e3ea - test: after
+  +edited
+  +=======
+   before
+  +>>>>>>> destination:  f013c8cc5b24 - test: before
+   middle
+  +last
+  diff -r f013c8cc5b24 foo
+  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+  +++ b/foo	Thu Jan 01 00:00:00 1970 +0000
+  @@ -0,0 +1,1 @@
+  +foo
+
+  $ hg up --abort
+  update aborted
+
+Make sure diff is same as it was before running hg update
+  $ hg diff
+  diff -r fd93e7c2e3ea file
+  --- a/file	Thu Jan 01 00:00:00 1970 +0000
+  +++ b/file	Thu Jan 01 00:00:00 1970 +0000
+  @@ -1,2 +1,3 @@
+  -after
+  +edited
+   middle
+  +last
+  diff -r fd93e7c2e3ea foo
+  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+  +++ b/foo	Thu Jan 01 00:00:00 1970 +0000
+  @@ -0,0 +1,1 @@
+  +foo
+
+Error out if there is no interrupted update
+  $ hg up --abort
+  abort: no interrupted update exists
+  [255]