diff --git a/bookwyrm/models/import_job.py b/bookwyrm/models/import_job.py
index 387261f0..97b93b97 100644
--- a/bookwyrm/models/import_job.py
+++ b/bookwyrm/models/import_job.py
@@ -205,7 +205,9 @@ class ImportItem(models.Model):
         if start_date and start_date is not None and not self.date_read:
             return [ReadThrough(start_date=start_date)]
         if self.date_read:
-            start_date = start_date if start_date < self.date_read else None
+            start_date = (
+                start_date if start_date and start_date < self.date_read else None
+            )
             return [
                 ReadThrough(
                     start_date=start_date,