diff --git a/imio_teleservices_templatetags/templatetags/imio_teleservices.py b/imio_teleservices_templatetags/templatetags/imio_teleservices.py
index 0fb3c20..f115969 100644
--- a/imio_teleservices_templatetags/templatetags/imio_teleservices.py
+++ b/imio_teleservices_templatetags/templatetags/imio_teleservices.py
@@ -72,6 +72,16 @@ def diff_dates(oldest_date, newest_date):
     return str(diff)
 
 
+@register.filter
+def get_birthday_from_nn(numero_national):
+    """
+    numero_national : (str) numero national peut contenir espace . et -
+    """
+    numero_national = clean_string(numero_national)
+    date = numero_national[:6]
+    return datetime.datetime.strptime(date, "%y%m%d")
+
+
 @register.filter
 def is_valid_tva_number(tva_number, formatage=True):
     """