diff --git a/papers/repo.py b/papers/repo.py
index 0113468..8f67424 100644
--- a/papers/repo.py
+++ b/papers/repo.py
@@ -136,9 +136,23 @@ class Repository(object):
             and new_citekey in self):
             raise CiteKeyCollision('citekey {} already in use'.format(
                                    new_citekey))
+
         self.remove_paper(paper.citekey, remove_doc = False)
+        old_citekey = paper.citekey
         paper.citekey = new_citekey
         self.add_paper(paper, overwrite = overwrite)
+        self._move_doc(old_citekey, paper)
+
+    def _move_doc(self, old_citekey, paper):
+        """Fragile. Make more robust"""
+        try:
+            old_docfile = self.find_document(old_citekey)
+            ext = os.path.splitext(old_docfile)[1]
+            new_docfile = os.path.join(self.doc_dir, paper.citekey + ext)
+            shutil.move(old_docfile, new_docfile)
+            paper.set_external_document(new_docfile)
+        except NoDocumentFile:
+            pass
 
     def _bibfile(self, citekey):
         return os.path.join(self.bib_dir, citekey + '.bibyaml')
@@ -176,14 +190,21 @@ class Repository(object):
             if not citekey + _base27(n) in self.citekeys:
                 return citekey + _base27(n)
 
+    def find_document(self, citekey):
+        found = glob.glob('{}/{}.*'.format(self.doc_dir, citekey))
+        if found:
+            return found[0]
+        else:
+            raise NoDocumentFile
+
     def import_document(self, citekey, doc_file):
         if citekey not in self.citekeys:
-            raise ValueError("Unknown citekey {}.".format(citekey))
+            raise(ValueError, "Unknown citekey: %s." % citekey)
         else:
             if not os.path.isfile(doc_file):
                 raise ValueError("No file {} found.".format(doc_file))
-            new_doc_file = os.path.join(self.doc_dir,
-                                        os.path.basename(doc_file))
+            ext = os.path.splitext(doc_file)[1]
+            new_doc_file = os.path.join(self.doc_dir, citekey + ext)
             shutil.copy(doc_file, new_doc_file)
 
     def get_tags(self):
diff --git a/tests/test_repo.py b/tests/test_repo.py
index 0b8098a..58ef258 100644
--- a/tests/test_repo.py
+++ b/tests/test_repo.py
@@ -101,7 +101,7 @@ class TestUpdatePaper(TestRepo):
                                   os.path.join(os.path.dirname(__file__),
                                                'data/pagerank.pdf'))
         self.repo.rename_paper(self.repo.get_paper('Turing1950'), 'Doe2003')
-        # self.assertFalse(os.path.exists(os.path.join(
-        #     self.repo.doc_dir, 'Turing1950.pdf')))
-        # self.assertTrue(os.path.exists(os.path.join(
-        #     self.repo.doc_dir, 'Doe2013.pdf')))
+        self.assertFalse(os.path.exists(os.path.join(
+            self.repo.doc_dir, 'Turing1950.pdf')))
+        self.assertTrue(os.path.exists(os.path.join(
+            self.repo.doc_dir, 'Doe2003.pdf')))
diff --git a/tests/test_usecase.py b/tests/test_usecase.py
index 79590a1..16d008d 100644
--- a/tests/test_usecase.py
+++ b/tests/test_usecase.py
@@ -1,10 +1,11 @@
-import sys, os
+import sys, os, shutil, glob
 import unittest
 import pkgutil
 
 import testenv
 import fake_filesystem
 import fake_filesystem_shutil
+import fake_filesystem_glob
 
 from papers import papers_cmd
 from papers import color
@@ -12,23 +13,27 @@ from papers.p3 import io
 
 real_os = os
 real_open = open
+real_shutil = shutil
+real_glob = glob
 
-fake_os, fake_open, fake_shutil = None, None, None
+fake_os, fake_open, fake_shutil, fake_glob = None, None, None, None
 
 def _create_fake_fs():
-    global fake_os, fake_open, fake_shutil
+    global fake_os, fake_open, fake_shutil, fake_glob
 
     fake_fs = fake_filesystem.FakeFilesystem()
     fake_os = fake_filesystem.FakeOsModule(fake_fs)
     fake_open = fake_filesystem.FakeFileOpen(fake_fs)
     fake_shutil = fake_filesystem_shutil.FakeShutilModule(fake_fs)
+    fake_glob = fake_filesystem_glob.FakeGlobModule(fake_fs)
 
     fake_fs.CreateDirectory(fake_os.path.expanduser('~'))
     __builtins__['open'] = fake_open
     __builtins__['file'] = fake_open
 
-    sys.modules['os'] = fake_os
+    sys.modules['os']     = fake_os
     sys.modules['shutil'] = fake_shutil
+    sys.modules['glob']   = fake_glob
 
     import papers
     for importer, modname, ispkg in pkgutil.walk_packages(
@@ -102,7 +107,7 @@ class TestAdd(unittest.TestCase):
 
         papers_cmd.execute('papers init -p /not_default'.split())
         papers_cmd.execute('papers add -b /data/pagerank.bib -d /data/pagerank.pdf'.split())
-        self.assertEqual(set(fake_os.listdir('/not_default/doc')), {'pagerank.pdf'})
+        self.assertEqual(set(fake_os.listdir('/not_default/doc')), {'Page99.pdf'})
 
 
 class TestList(unittest.TestCase):