diff --git a/pinaxcon/proposals/models.py b/pinaxcon/proposals/models.py
index 8c18b15084f6c62c7ba26e02234706fa9e04c5a0..8adeb625336ad228c8b0904090cfa72bd6a7031b 100644
--- a/pinaxcon/proposals/models.py
+++ b/pinaxcon/proposals/models.py
@@ -87,7 +87,8 @@ class Proposal(ProposalBase):
 
     primary_topic = models.IntegerField(
         choices=PROPOSAL_TOPIC,
-        help_text="What is the primary topic area for your session?"
+        help_text="What is the primary topic area for your session?",
+        null=True,
     )
 
     experience_level = models.IntegerField(