diff --git a/sphinx/builders/__init__.py b/sphinx/builders/__init__.py
index 4e0a6cfce..4c2a16715 100644
--- a/sphinx/builders/__init__.py
+++ b/sphinx/builders/__init__.py
@@ -168,7 +168,9 @@ class Builder(object):
     def compile_all_catalogs(self):
         catalogs = i18n.get_catalogs(
             [path.join(self.srcdir, x) for x in self.config.locale_dirs],
-            self.config.language, self.config.gettext_compact, True)
+            self.config.language,
+            gettext_compact=self.config.gettext_compact,
+            force_all=True)
         message = 'all of %d po files' % len(catalogs)
         self.compile_catalogs(catalogs, message)
 
@@ -181,15 +183,17 @@ class Builder(object):
         specified_domains = set(map(to_domain, specified_files))
         catalogs = i18n.get_catalogs(
             [path.join(self.srcdir, x) for x in self.config.locale_dirs],
-            self.config.language, self.config.gettext_compact, True)
-        catalogs = [f for f in catalogs if f.domain in specified_domains]
+            self.config.language,
+            domains=list(specified_domains),
+            gettext_compact=self.config.gettext_compact)
         message = 'targets for %d po files that are specified' % len(catalogs)
         self.compile_catalogs(catalogs, message)
 
     def compile_update_catalogs(self):
         catalogs = i18n.get_catalogs(
             [path.join(self.srcdir, x) for x in self.config.locale_dirs],
-            self.config.language, self.config.gettext_compact)
+            self.config.language,
+            gettext_compact=self.config.gettext_compact)
         message = 'targets for %d po files that are out of date' % len(catalogs)
         self.compile_catalogs(catalogs, message)
 
diff --git a/sphinx/locale/__init__.py b/sphinx/locale/__init__.py
index acb71bf28..db8081516 100644
--- a/sphinx/locale/__init__.py
+++ b/sphinx/locale/__init__.py
@@ -208,6 +208,15 @@ def init(locale_dirs, language, catalog='sphinx'):
         translator = None
     # the None entry is the system's default locale path
     has_translation = True
+
+    # compile mo files if po file is updated
+    # TODO: remove circular importing
+    from sphinx.util.i18n import get_catalogs
+    for catinfo in get_catalogs(locale_dirs, language, domains=[catalog],
+                                force_all=False):
+        catinfo.write_mo(language)
+
+    # loading
     for dir_ in locale_dirs:
         try:
             trans = gettext.translation(catalog, localedir=dir_,
diff --git a/sphinx/util/i18n.py b/sphinx/util/i18n.py
index 7bd0c34ea..e83ba4052 100644
--- a/sphinx/util/i18n.py
+++ b/sphinx/util/i18n.py
@@ -16,6 +16,7 @@ from babel.messages.pofile import read_po
 from babel.messages.mofile import write_mo
 
 from sphinx.util.osutil import walk
+from sphinx.util import SEP
 
 
 LocaleFileInfoBase = namedtuple('CatalogInfo', 'base_dir,domain')
@@ -50,13 +51,16 @@ class CatalogInfo(LocaleFileInfoBase):
                 write_mo(mo, read_po(po, locale))
 
 
-def get_catalogs(locale_dirs, locale, gettext_compact=False, force_all=False):
+def get_catalogs(locale_dirs, locale, domains=None,
+                 gettext_compact=False, force_all=False):
     """
     :param list locale_dirs:
        list of path as `['locale_dir1', 'locale_dir2', ...]` to find
        translation catalogs. Each path contains a structure such as
        `<locale>/LC_MESSAGES/domain.po`.
     :param str locale: a language as `'en'`
+    :param list domains: list of domain names to get. If empty list or None
+       is specified, get all domain names. default is None.
     :param boolean gettext_compact:
        * False: keep domains directory structure (default).
        * True: domains in the sub directory will be merged into 1 file.
@@ -70,6 +74,9 @@ def get_catalogs(locale_dirs, locale, gettext_compact=False, force_all=False):
 
     catalogs = set()
     for locale_dir in locale_dirs:
+        if not locale_dir:
+            continue  # skip system locale directory
+
         base_dir = path.join(locale_dir, locale, 'LC_MESSAGES')
 
         if not path.exists(base_dir):
@@ -82,6 +89,9 @@ def get_catalogs(locale_dirs, locale, gettext_compact=False, force_all=False):
                 domain = path.relpath(path.join(dirpath, base), base_dir)
                 if gettext_compact and path.sep in domain:
                     domain = path.split(domain)[0]
+                domain = domain.replace(path.sep, SEP)
+                if domains and domain not in domains:
+                    continue
                 cat = CatalogInfo(base_dir, domain)
                 if force_all or cat.is_outdated():
                     catalogs.add(cat)
diff --git a/tests/test_catalogs.py b/tests/test_catalogs.py
index b06e71a57..7b1cc05e0 100644
--- a/tests/test_catalogs.py
+++ b/tests/test_catalogs.py
@@ -55,10 +55,13 @@ def test_compile_all_catalogs(app, status, warning):
 @with_app(buildername='html',  testroot='intl',
           confoverrides={'language': 'en', 'locale_dirs': [locale_dir]})
 def test_compile_specific_catalogs(app, status, warning):
-    app.builder.compile_specific_catalogs(['admonitions'])
-
     catalog_dir = locale_dir / app.config.language / 'LC_MESSAGES'
-    actual = set(find_files(catalog_dir, '.mo'))
+    def get_actual():
+        return set(find_files(catalog_dir, '.mo'))
+
+    actual_on_boot = get_actual()  # sphinx.mo might be included
+    app.builder.compile_specific_catalogs(['admonitions'])
+    actual = get_actual() - actual_on_boot
     assert actual == set(['admonitions.mo'])
 
 
diff --git a/tests/test_util_i18n.py b/tests/test_util_i18n.py
index ba18026ca..d8f0cd012 100644
--- a/tests/test_util_i18n.py
+++ b/tests/test_util_i18n.py
@@ -77,8 +77,8 @@ def test_get_catalogs_for_xx(dir):
     assert domains == set([
         'test1',
         'test2',
-        path.normpath('sub/test4'),
-        path.normpath('sub/test5'),
+        'sub/test4',
+        'sub/test5',
     ])
 
 
@@ -131,8 +131,8 @@ def test_get_catalogs_for_xx_without_outdated(dir):
     assert domains == set([
         'test1',
         'test2',
-        path.normpath('sub/test4'),
-        path.normpath('sub/test5'),
+        'sub/test4',
+        'sub/test5',
     ])