diff --git a/rhodecode/controllers/compare.py b/rhodecode/controllers/compare.py
--- a/rhodecode/controllers/compare.py
+++ b/rhodecode/controllers/compare.py
@@ -26,12 +26,15 @@
 import logging
 import traceback
 
+from webob.exc import HTTPNotFound
 from pylons import request, response, session, tmpl_context as c, url
 from pylons.controllers.util import abort, redirect
 
 from rhodecode.lib.base import BaseRepoController, render
 from rhodecode.lib.auth import LoginRequired, HasRepoPermissionAnyDecorator
-from webob.exc import HTTPNotFound
+from rhodecode.lib import diffs
+
+from rhodecode.model.db import Repository
 
 log = logging.getLogger(__name__)
 
@@ -47,7 +50,8 @@ class CompareController(BaseRepoControll
     def _handle_ref(self, ref):
         """
         Parse the org...other string
-        Possible formats are `(branch|book|tag):<name>...(branch|book|tag):<othername>`
+        Possible formats are 
+            `(branch|book|tag):<name>...(branch|book|tag):<othername>`
 
         :param ref: <orginal_reference>...<other_reference>
         :type ref: str
@@ -64,7 +68,8 @@ class CompareController(BaseRepoControll
             _repo = org_repo
             name, val = other.split(':')
             if _other_repo:
-                _repo = _other_repo #TODO: do an actual repo loookup within rhodecode
+                #TODO: do an actual repo loookup within rhodecode
+                _repo = _other_repo
 
             return _repo, (name, val)
 
@@ -79,17 +84,47 @@ class CompareController(BaseRepoControll
 
         raise HTTPNotFound
 
+    def _get_changesets(self, org_repo, org_ref, other_repo, other_ref):
+        changesets = []
+        #case two independent repos
+        if org_repo != other_repo:
+            from mercurial import discovery
+            import binascii
+            out = discovery.findcommonoutgoing(org_repo._repo, other_repo._repo)
+            for cs in map(binascii.hexlify, out.missing):
+                changesets.append(org_repo.get_changeset(cs))
+        else:
+            for cs in map(binascii.hexlify, out):
+                changesets.append(org_repo.get_changeset(cs))
+
+        return changesets
+
     def index(self, ref):
-
         org_repo, org_ref, other_repo, other_ref = self._handle_ref(ref)
-        return '''
-        <pre>
-        REPO: %s 
-        REF: %s 
+
+        c.org_repo = org_repo = Repository.get_by_repo_name(org_repo)
+        c.other_repo = other_repo = Repository.get_by_repo_name(other_repo)
+
+        c.cs_ranges = self._get_changesets(org_repo.scm_instance,
+                                           org_ref,
+                                           other_repo.scm_instance,
+                                           other_ref)
+
+        c.org_ref = org_ref[1]
+        c.other_ref = other_ref[1]
+        cs1 = org_repo.scm_instance.get_changeset(org_ref[1])
+        cs2 = other_repo.scm_instance.get_changeset(other_ref[1])
+
+        _diff = diffs.differ(org_repo, org_ref, other_repo, other_ref)
+        diff_processor = diffs.DiffProcessor(_diff, format='gitdiff')
+
+        diff = diff_processor.as_html(enable_comments=False)
+        stats = diff_processor.stat()
+
+        c.changes = [('change?', None, diff, cs1, cs2, stats,)]
+
+        return render('compare/compare_diff.html')
+
+
+
         
-        vs 
-        
-        REPO: %s 
-        REF: %s        
-        </pre>
-        ''' % (org_repo, org_ref, other_repo, other_ref)