diff --git a/ucs-school-4.0/ucs-school-umc-csv-import/umc/python/schoolcsvimport/util.py b/ucs-school-4.0/ucs-school-umc-csv-import/umc/python/schoolcsvimport/util.py
index d684ddf..7620710 100644
--- a/ucs-school-4.0/ucs-school-umc-csv-import/umc/python/schoolcsvimport/util.py
+++ b/ucs-school-4.0/ucs-school-umc-csv-import/umc/python/schoolcsvimport/util.py
@@ -186,7 +204,9 @@ def to_dict(self, format_birthday):
 		if format_birthday:
 			# force format of date as requested, not as seen in LDAP
 			try:
-				attrs['birthday'] = format_date(attrs['birthday'].replace(' ', ''), format_birthday)
+				if attrs['birthday']:
+					attrs['birthday'] = attrs['birthday'].replace(' ', '')
+				attrs['birthday'] = format_date(attrs['birthday'], format_birthday)
 			except (TypeError, ValueError):
 				pass
 		attrs['errors'] = self.errors