diff --git a/smash/web/importer/csv_subject_import_reader.py b/smash/web/importer/csv_subject_import_reader.py
index 54883161816a39679abf1d6697a90e4374d21a1c..187b59aba9d98798f8630054828256aa3b80b07f 100644
--- a/smash/web/importer/csv_subject_import_reader.py
+++ b/smash/web/importer/csv_subject_import_reader.py
@@ -60,7 +60,12 @@ class CsvSubjectImportReader(SubjectImportReader):
     def get_new_date_value(self, old_value, column_name, new_value):
         # type: (datetime,unicode,unicode) ->  datetime
         if old_value is None or old_value == "":
-            return datetime.datetime.strptime(new_value, CSV_DATE_FORMAT)
+            try:
+                result = datetime.datetime.strptime(new_value, CSV_DATE_FORMAT)
+            except ValueError:
+                logger.warn("Invalid date: " + new_value)
+                result = old_value
+            return result
         if new_value is None or new_value == "":
             return old_value
         logger.warn(
diff --git a/smash/web/tests/data/import_date_of_birth.csv b/smash/web/tests/data/import_date_of_birth.csv
new file mode 100644
index 0000000000000000000000000000000000000000..43d9adb8ac452c865ffcbdb96446f22847873c61
--- /dev/null
+++ b/smash/web/tests/data/import_date_of_birth.csv
@@ -0,0 +1,4 @@
+first_name,last_name,participant_id,date_born
+Piotr,Gawron,Cov-000001,
+Piotr,Gawron,Cov-000002,invalid
+Piotr,Gawron,Cov-000003,2222-20-20
\ No newline at end of file
diff --git a/smash/web/tests/importer/test_csv_subject_import_reader.py b/smash/web/tests/importer/test_csv_subject_import_reader.py
index 798465180ed959ad7a5ae93415ca509eec33d85f..a80f323469577c13837ee6bf83c6ed1baebd004c 100644
--- a/smash/web/tests/importer/test_csv_subject_import_reader.py
+++ b/smash/web/tests/importer/test_csv_subject_import_reader.py
@@ -27,3 +27,11 @@ class TestCsvReader(TestCase):
         self.assertEqual(2020, study_subject.subject.date_born.year)
 
         self.assertIsNotNone(study_subject.study)
+
+    def test_load_problematic_dates(self):
+        filename = get_resource_path('import_date_of_birth.csv')
+        study_subjects = CsvSubjectImportReader().load_data(filename)
+        self.assertEqual(3, len(study_subjects))
+        self.assertIsNone(study_subjects[0].subject.date_born)
+        self.assertIsNone(study_subjects[1].subject.date_born)
+        self.assertIsNone(study_subjects[2].subject.date_born)