diff --git a/beets/library.py b/beets/library.py
index 0b2513df5..f676bc49e 100644
--- a/beets/library.py
+++ b/beets/library.py
@@ -66,7 +66,7 @@ ITEM_FIELDS = [
     ('length',      'real', False, True),
     ('bitrate',     'int',  False, True),
     ('format',      'text', False, True),
-    ('file_mtime',  'int', False, False),
+    ('mtime',       'int',  False, False),
 ]
 ITEM_KEYS_WRITABLE = [f[0] for f in ITEM_FIELDS if f[3] and f[2]]
 ITEM_KEYS_META     = [f[0] for f in ITEM_FIELDS if f[3]]
@@ -200,6 +200,10 @@ class Item(object):
         for key in ITEM_KEYS_META:
             setattr(self, key, getattr(f, key))
         self.path = read_path
+
+        # Database's mtime should now reflect the on-disk value.
+        if read_path == self.path:
+            self.mtime = self.current_mtime()
     
     def write(self):
         """Writes the item's metadata to the associated file.
@@ -208,9 +212,9 @@ class Item(object):
         for key in ITEM_KEYS_WRITABLE:
             setattr(f, key, getattr(self, key))
         f.save()
-        
-        # Set file modified time, we now know when beets last changed this file
-        setattr(self, 'file_mtime', os.path.getmtime(syspath(self.path)))
+
+        # The file has a new mtime.
+        self.mtime = self.current_mtime()
 
 
     # Files themselves.
@@ -226,9 +230,15 @@ class Item(object):
             
         # Either copying or moving succeeded, so update the stored path.
         self.path = dest
-        
-        # Update file modified time in the library
-        setattr(self, 'file_mtime', os.path.getmtime(syspath(self.path)))
+
+        # Update mtime to reflect the new file.
+        self.mtime = self.current_mtime()
+
+    def current_mtime(self):
+        """Returns the current mtime of the file, rounded to the nearest
+        integer.
+        """
+        return int(os.path.getmtime(syspath(self.path)))
 
 
 # Library queries.
diff --git a/beets/ui/commands.py b/beets/ui/commands.py
index 9648af526..fdbd5a377 100644
--- a/beets/ui/commands.py
+++ b/beets/ui/commands.py
@@ -725,9 +725,11 @@ def update_items(lib, query, album, move, color, pretend):
             continue
 
         # Did the item change since last checked?
-        if os.path.getmtime(syspath(item.path)) == getattr(item, 'file_mtime'):
+        if item.current_mtime() <= item.mtime:
+            log.debug(u'skipping %s because mtime is up to date (%i)' %
+                      (item.path, item.mtime))
             continue
-            
+
         # Read new data.
         old_data = dict(item.record)
         item.read()
@@ -761,12 +763,13 @@ def update_items(lib, query, album, move, color, pretend):
 
             lib.store(item)
             affected_albums.add(item.album_id)
-        else:
-            if not pretend:
-                # file_mtime is different, but no changes to the metadata.
-                # store the new mtime so we don't check this again in the future.
-                setattr(item, 'file_mtime', os.path.getmtime(syspath(item.path)))
-    
+        elif not pretend:
+            # The file's mtime was different, but there were no changes
+            # to the metadata. Store the new mtime, which is set in the
+            # call to read(), so we don't check this again in the
+            # future.
+            lib.store(item)
+
     # Skip album changes while pretending.
     if pretend:
         return
diff --git a/docs/changelog.rst b/docs/changelog.rst
index c8d4ab578..f019afe4f 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -26,6 +26,8 @@ Changelog
 * The importer now ignores certain "clutter" files like ``.AppleDouble``
   directories and ``._*`` files. The list of ignored patterns is configurable
   via the ``ignore`` setting; see :doc:`/reference/config`.
+* The database now keeps track of files' modification times so that, during
+  an ``update``, unmodified files can be skipped. (Thanks to Jos van der Til.)
 * Fix a crash after using the "as Tracks" option during import.
 * Fix a Unicode error when tagging items with missing titles.