diff --git a/beets/library.py b/beets/library.py
index dd0d83b94..ac890f560 100644
--- a/beets/library.py
+++ b/beets/library.py
@@ -225,8 +225,11 @@ class Item(object):
 
     def move(self, dest, copy=False):
         """Moves or copies the item's file, updating the path value if
-        the move succeeds.
+        the move succeeds. If a file exists at ``dest``, then it is
+        slightly modified to be unique.
         """
+        if not util.samefile(self.path, dest):
+            dest = util.unique_path(dest)
         if copy:
             util.copy(self.path, dest)
         else:
@@ -1264,6 +1267,7 @@ class Album(BaseAlbum):
         # Normal operation.
         if oldart == artdest:
             util.soft_remove(oldart)
+        artdest = util.unique_path(artdest)
         util.copy(path, artdest)
         self.artpath = artdest
 
diff --git a/beets/util/__init__.py b/beets/util/__init__.py
index a70148ca1..263ff5671 100644
--- a/beets/util/__init__.py
+++ b/beets/util/__init__.py
@@ -245,6 +245,27 @@ def move(path, dest, replace=False, pathmod=None):
     _assert_not_exists(dest, pathmod)
     return shutil.move(path, dest)
 
+def unique_path(path):
+    """Returns a version of ``path`` that does not exist on the
+    filesystem. Specifically, if ``path` itself already exists, then
+    something unique is appended to the path.
+    """
+    if not os.path.exists(syspath(path)):
+        return path
+
+    base, ext = os.path.splitext(path)
+    match = re.search(r'\.(\d)+$', base)
+    if match:
+        num = int(match.group(1))
+        base = base[:match.start()]
+    else:
+        num = 0
+    while True:
+        num += 1
+        new_path = '%s.%i%s' % (base, num, ext)
+        if not os.path.exists(new_path):
+            return new_path
+
 # Note: POSIX actually supports \ and : -- I just think they're
 # a pain. And ? has caused problems for some.
 CHAR_REPLACE = [
diff --git a/docs/changelog.rst b/docs/changelog.rst
index 75f8ce08e..347b6c757 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -15,6 +15,8 @@ This release focuses on making beets' path formatting vastly more powerful.
 * **Filename substitutions are now configurable** via the ``replace`` config
   value. You can choose which characters you think should be allowed in your
   directory and music file names.  See :doc:`/reference/config`.
+* Beets now ensures that files have **unique filenames** by appending a number
+  to any filename that would otherwise conflict with an existing file.
 * Fix an incompatibility in BPD with libmpc (the library that powers mpc and
   ncmpc).
 * Fix a crash when importing a partial match whose first track was missing.
diff --git a/test/test_files.py b/test/test_files.py
index bf61ea0d8..188d9be56 100644
--- a/test/test_files.py
+++ b/test/test_files.py
@@ -113,6 +113,17 @@ class MoveTest(unittest.TestCase, _common.ExtraAsserts):
             # Make everything writable so it can be cleaned up.
             os.chmod(self.path, 0777)
             os.chmod(self.i.path, 0777)
+
+    def test_move_avoids_collision_with_existing_file(self):
+        # Make a conflicting file at the destination.
+        dest = self.lib.destination(self.i)
+        os.makedirs(os.path.dirname(dest))
+        touch(dest)
+
+        self.lib.move(self.i)
+        self.assertNotEqual(self.i.path, dest)
+        self.assertEqual(os.path.dirname(self.i.path),
+                         os.path.dirname(dest))
     
 class HelperTest(unittest.TestCase):
     def test_ancestry_works_on_file(self):
@@ -296,6 +307,25 @@ class ArtFileTest(unittest.TestCase, _common.ExtraAsserts):
         ai.set_art(artdest)
         self.assertTrue(os.path.exists(ai.artpath))
 
+    def test_setart_to_conflicting_file_gets_new_path(self):
+        newart = os.path.join(self.libdir, 'newart.jpg')
+        touch(newart)
+        i2 = item()
+        i2.path = self.i.path
+        i2.artist = 'someArtist'
+        ai = self.lib.add_album((i2,))
+        self.lib.move(i2, True)
+
+        # Make a file at the destination.
+        artdest = ai.art_destination(newart)
+        touch(artdest)
+
+        # Set the art.
+        ai.set_art(newart)
+        self.assertNotEqual(artdest, ai.artpath)
+        self.assertEqual(os.path.dirname(artdest),
+                         os.path.dirname(ai.artpath))
+
     def test_setart_sets_permissions(self):
         os.remove(self.art)
 
@@ -533,6 +563,34 @@ class WalkTest(unittest.TestCase):
         self.assertEqual(res[0],
                          (self.base, [], []))
 
+class UniquePathTest(unittest.TestCase):
+    def setUp(self):
+        self.base = os.path.join(_common.RSRC, 'testdir')
+        os.mkdir(self.base)
+        touch(os.path.join(self.base, 'x.mp3'))
+        touch(os.path.join(self.base, 'x.1.mp3'))
+        touch(os.path.join(self.base, 'x.2.mp3'))
+        touch(os.path.join(self.base, 'y.mp3'))
+    def tearDown(self):
+        if os.path.exists(self.base):
+            shutil.rmtree(self.base)
+
+    def test_new_file_unchanged(self):
+        path = util.unique_path(os.path.join(self.base, 'z.mp3'))
+        self.assertEqual(path, os.path.join(self.base, 'z.mp3'))
+
+    def test_conflicting_file_appends_1(self):
+        path = util.unique_path(os.path.join(self.base, 'y.mp3'))
+        self.assertEqual(path, os.path.join(self.base, 'y.1.mp3'))
+
+    def test_conflicting_file_appends_higher_number(self):
+        path = util.unique_path(os.path.join(self.base, 'x.mp3'))
+        self.assertEqual(path, os.path.join(self.base, 'x.3.mp3'))
+
+    def test_conflicting_file_with_number_increases_number(self):
+        path = util.unique_path(os.path.join(self.base, 'x.1.mp3'))
+        self.assertEqual(path, os.path.join(self.base, 'x.3.mp3'))
+
 def suite():
     return unittest.TestLoader().loadTestsFromName(__name__)