diff --git a/addons/project/project.py b/addons/project/project.py
index d83f4a8d424..c3a3ef7f5bf 100644
--- a/addons/project/project.py
+++ b/addons/project/project.py
@@ -84,35 +84,70 @@ class project(osv.osv):
             val['pricelist_id'] = pricelist_id
         return {'value': val}
 
-    def _progress_rate(self, cr, uid, ids, names, arg, context=None):
-        res = {}.fromkeys(ids, 0.0)
-        if not ids:
-            return res
-        cr.execute('''SELECT
-                project_id, sum(planned_hours), sum(total_hours), sum(effective_hours), SUM(remaining_hours)
-            FROM
-                project_task
-            WHERE
-                project_id in %s AND
-                state<>'cancelled'
-            GROUP BY
-                project_id''', (tuple(ids),))
-        progress = dict(map(lambda x: (x[0], (x[1],x[2],x[3],x[4])), cr.fetchall()))
-        for project in self.browse(cr, uid, ids, context=context):
-            s = progress.get(project.id, (0.0,0.0,0.0,0.0))
-            res[project.id] = {
-                'planned_hours': s[0],
-                'effective_hours': s[2],
-                'total_hours': s[1],
-                'progress_rate': s[1] and round(100.0*s[2]/s[1],2) or 0.0
-            }
+    def _get_projects_from_tasks(self, cr, uid, task_ids, context=None):
+        tasks = self.pool.get('project.task').browse(cr, uid, task_ids, context=context)
+        project_ids = [task.project_id.id for task in tasks]
+        return self.pool.get('project.project')._get_project_and_parents(cr, uid, project_ids, context)
+
+    def _get_project_and_parents(self, cr, uid, ids, context=None):
+        """ return the project ids and all their parent projects """
+        res = set(ids)
+        while ids:
+            cr.execute("""
+                SELECT DISTINCT parent.id
+                FROM project_project project, project_project parent, account_analytic_account account
+                WHERE project.analytic_account_id = account.id
+                AND parent.analytic_account_id = account.parent_id
+                AND project.id IN %s
+                """, (tuple(ids),))
+            ids = [t[0] for t in cr.fetchall()]
+            res.update(ids)
+        return list(res)
+
+    def _get_project_and_children(self, cr, uid, ids, context=None):
+        """ retrieve all children projects of project ids;
+            return a dictionary mapping each project to its parent project (or None)
+        """
+        res = dict.fromkeys(ids, None)
+        while ids:
+            cr.execute("""
+                SELECT project.id, parent.id
+                FROM project_project project, project_project parent, account_analytic_account account
+                WHERE project.analytic_account_id = account.id
+                AND parent.analytic_account_id = account.parent_id
+                AND parent.id IN %s
+                """, (tuple(ids),))
+            dic = dict(cr.fetchall())
+            res.update(dic)
+            ids = dic.keys()
         return res
 
-    def _get_project_task(self, cr, uid, ids, context=None):
-        result = {}
-        for task in self.pool.get('project.task').browse(cr, uid, ids, context=context):
-            if task.project_id: result[task.project_id.id] = True
-        return result.keys()
+    def _progress_rate(self, cr, uid, ids, names, arg, context=None):
+        child_parent = self._get_project_and_children(cr, uid, ids, context)
+        # compute planned_hours, total_hours, effective_hours specific to each project
+        cr.execute("""
+            SELECT project_id, COALESCE(SUM(planned_hours), 0.0),
+                COALESCE(SUM(total_hours), 0.0), COALESCE(SUM(effective_hours), 0.0)
+            FROM project_task WHERE project_id IN %s AND state <> 'cancelled'
+            GROUP BY project_id
+            """, (tuple(child_parent.keys()),))
+        # aggregate results into res
+        res = dict([(id, {'planned_hours':0.0,'total_hours':0.0,'effective_hours':0.0}) for id in ids])
+        for id, planned, total, effective in cr.fetchall():
+            # add the values specific to id to all parent projects of id in the result
+            while id:
+                if id in ids:
+                    res[id]['planned_hours'] += planned
+                    res[id]['total_hours'] += total
+                    res[id]['effective_hours'] += effective
+                id = child_parent[id]
+        # compute progress rates
+        for id in ids:
+            if res[id]['total_hours']:
+                res[id]['progress_rate'] = round(100.0 * res[id]['effective_hours'] / res[id]['total_hours'], 2)
+            else:
+                res[id]['progress_rate'] = 0.0
+        return res
 
     def unlink(self, cr, uid, ids, *args, **kwargs):
         for proj in self.browse(cr, uid, ids):
@@ -133,17 +168,25 @@ class project(osv.osv):
         'tasks': fields.one2many('project.task', 'project_id', "Project tasks"),
         'planned_hours': fields.function(_progress_rate, multi="progress", string='Planned Time', help="Sum of planned hours of all tasks related to this project and its child projects.",
             store = {
-                'project.project': (lambda self, cr, uid, ids, c={}: ids, ['tasks'], 10),
-                'project.task': (_get_project_task, ['planned_hours', 'effective_hours', 'remaining_hours', 'total_hours', 'progress', 'delay_hours','state'], 10),
+                'project.project': (_get_project_and_parents, ['tasks', 'parent_id', 'child_ids'], 10),
+                'project.task': (_get_projects_from_tasks, ['planned_hours', 'remaining_hours', 'work_ids', 'state'], 20),
+            }),
+        'effective_hours': fields.function(_progress_rate, multi="progress", string='Time Spent', help="Sum of spent hours of all tasks related to this project and its child projects.",
+            store = {
+                'project.project': (_get_project_and_parents, ['tasks', 'parent_id', 'child_ids'], 10),
+                'project.task': (_get_projects_from_tasks, ['planned_hours', 'remaining_hours', 'work_ids', 'state'], 20),
             }),
-        'effective_hours': fields.function(_progress_rate, multi="progress", string='Time Spent', help="Sum of spent hours of all tasks related to this project and its child projects."),
-        'resource_calendar_id': fields.many2one('resource.calendar', 'Working Time', help="Timetable working hours to adjust the gantt diagram report", states={'close':[('readonly',True)]} ),
         'total_hours': fields.function(_progress_rate, multi="progress", string='Total Time', help="Sum of total hours of all tasks related to this project and its child projects.",
             store = {
-                'project.project': (lambda self, cr, uid, ids, c={}: ids, ['tasks'], 10),
-                'project.task': (_get_project_task, ['planned_hours', 'effective_hours', 'remaining_hours', 'total_hours', 'progress', 'delay_hours','state'], 10),
+                'project.project': (_get_project_and_parents, ['tasks', 'parent_id', 'child_ids'], 10),
+                'project.task': (_get_projects_from_tasks, ['planned_hours', 'remaining_hours', 'work_ids', 'state'], 20),
             }),
-        'progress_rate': fields.function(_progress_rate, multi="progress", string='Progress', type='float', group_operator="avg", help="Percent of tasks closed according to the total of tasks todo."),
+        'progress_rate': fields.function(_progress_rate, multi="progress", string='Progress', type='float', group_operator="avg", help="Percent of tasks closed according to the total of tasks todo.",
+            store = {
+                'project.project': (_get_project_and_parents, ['tasks', 'parent_id', 'child_ids'], 10),
+                'project.task': (_get_projects_from_tasks, ['planned_hours', 'remaining_hours', 'work_ids', 'state'], 20),
+            }),
+        'resource_calendar_id': fields.many2one('resource.calendar', 'Working Time', help="Timetable working hours to adjust the gantt diagram report", states={'close':[('readonly',True)]} ),
         'warn_customer': fields.boolean('Warn Partner', help="If you check this, the user will have a popup when closing a task that propose a message to send by email to the customer.", states={'close':[('readonly',True)], 'cancelled':[('readonly',True)]}),
         'warn_header': fields.text('Mail Header', help="Header added at the beginning of the email for the warning message sent to the customer when a task is closed.", states={'close':[('readonly',True)], 'cancelled':[('readonly',True)]}),
         'warn_footer': fields.text('Mail Footer', help="Footer added at the beginning of the email for the warning message sent to the customer when a task is closed.", states={'close':[('readonly',True)], 'cancelled':[('readonly',True)]}),