diff --git a/addons/hr/hr.py b/addons/hr/hr.py
index 49eaba043f9..bc56934c7c3 100644
--- a/addons/hr/hr.py
+++ b/addons/hr/hr.py
@@ -166,8 +166,8 @@ class hr_timesheet(osv.osv):
 		'name' : fields.char("Name", size=64, required=True),
 		'dayofweek': fields.selection([('0','Monday'),('1','Tuesday'),('2','Wednesday'),('3','Thursday'),('4','Friday'),('5','Saturday'),('6','Sunday')], 'Day of week'),
 		'date_from' : fields.date('Starting date'),
-		'hour_from' : fields.char('Work from', size=8),
-		'hour_to' : fields.char("Work to", size=8),
+		'hour_from' : fields.char('Work from', size=8, required=True),
+		'hour_to' : fields.char("Work to", size=8, required=True),
 		'tgroup_id' : fields.many2one("hr.timesheet.group", "Employee's timesheet group", select=True),
 	}
 	_order = 'dayofweek, hour_from'