diff --git a/issue/middleware.py b/issue/middleware.py
index f0169f3..1328ccb 100644
--- a/issue/middleware.py
+++ b/issue/middleware.py
@@ -1,18 +1,46 @@
+from django.core.exceptions import ImproperlyConfigured
 from django.core.exceptions import ObjectDoesNotExist
 from django.http import HttpResponseForbidden
 from django.contrib.auth.decorators import login_required
+from django.db.models import Q
 
 from issue.models import *
 
 
 class ProjectMiddleware:
+    """
+    This middleware must be call after authentication middleware.
+    """
 
     def process_view(self, request, view, view_args, view_kwargs):
 
         if view.__module__ != 'issue.views':
             return
 
-        projects = Project.objects.filter(public=True)
+        if not hasattr(request, 'user'):
+            raise ImproperlyConfigured(
+                "The project middleware requires the"
+                " authentication middleware to be installed.  Edit your"
+                " MIDDLEWARE_CLASSES setting to insert"
+                " 'django.contrib.auth.middleware.AuthenticationMiddleware'"
+                " before the ProjectMiddleware class.")
+
+        user = None
+        if request.user.is_authenticated():
+            user = User.objects.get(username=request.user)
+
+        query = Q(public=True)
+        if user:
+            # access granted through a team
+            query |= Q(permissions__grantee_type=PermissionModel.GRANTEE_TEAM,
+                    permissions__grantee_name__in=user.teams.values_list('name'))
+            # access granted through a group
+            query |= Q(permissions__grantee_type=PermissionModel.GRANTEE_GROUP,
+                    permissions__grantee_name__in=user.groups.values_list('name'))
+            # access granted by specific permission
+            query |= Q(permissions__grantee_type=PermissionModel.GRANTEE_USER,
+                    permissions__grantee_name=user.username)
+        projects = Project.objects.filter(query)
         request.projects = projects
 
         project = view_kwargs.get('project')