diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -1713,6 +1713,8 @@ def log(ui, repo, *pats, **opts):
     if opts["date"]:
         df = util.matchdate(opts["date"])
 
+    only_branches = opts['only_branch']
+
     displayer = cmdutil.show_changeset(ui, repo, opts, True, matchfn)
     for st, rev, fns in changeiter:
         if st == 'add':
@@ -1724,6 +1726,11 @@ def log(ui, repo, *pats, **opts):
             if opts['only_merges'] and len(parents) != 2:
                 continue
 
+            if only_branches:
+                revbranch = get(rev)[5]['branch']
+                if revbranch not in only_branches:
+                    continue
+
             if df:
                 changes = get(rev)
                 if not df(changes[2][0]):
@@ -2930,6 +2937,8 @@ table = {
           ('M', 'no-merges', None, _('do not show merges')),
           ('', 'style', '', _('display using template map file')),
           ('m', 'only-merges', None, _('show only merges')),
+          ('b', 'only-branch', [],
+            _('show only changesets within the given named branch')),
           ('p', 'patch', None, _('show patch')),
           ('P', 'prune', [], _('do not display revision or any of its ancestors')),
           ('', 'template', '', _('display with template')),
diff --git a/tests/test-branches b/tests/test-branches
--- a/tests/test-branches
+++ b/tests/test-branches
@@ -34,3 +34,9 @@ hg commit -d '5 0' -u test -m "Adding c 
 hg branches
 echo '-------'
 hg branches -a
+
+echo "--- Branch a"
+hg log -b a
+
+echo "---- Branch b"
+hg log -b b
diff --git a/tests/test-branches.out b/tests/test-branches.out
--- a/tests/test-branches.out
+++ b/tests/test-branches.out
@@ -10,3 +10,31 @@ default                        0:19709c5
 -------
 c                              5:5ca481e59b8c
 a                              1:dd6b440dd85a
+--- Branch a
+changeset:   1:dd6b440dd85a
+branch:      a
+user:        test
+date:        Thu Jan 01 00:00:01 1970 +0000
+summary:     Adding a branch
+
+---- Branch b
+changeset:   4:22df7444f7c1
+branch:      b
+parent:      2:ac22033332d1
+user:        test
+date:        Thu Jan 01 00:00:04 1970 +0000
+summary:     Adding b branch head 2
+
+changeset:   3:aee39cd168d0
+branch:      b
+user:        test
+date:        Thu Jan 01 00:00:03 1970 +0000
+summary:     Adding b branch head 1
+
+changeset:   2:ac22033332d1
+branch:      b
+parent:      0:19709c5a4e75
+user:        test
+date:        Thu Jan 01 00:00:02 1970 +0000
+summary:     Adding b branch
+