diff --git a/markets/storageadapter/dealpublisher.go b/markets/storageadapter/dealpublisher.go
index c2864bdf9..419bc6a04 100644
--- a/markets/storageadapter/dealpublisher.go
+++ b/markets/storageadapter/dealpublisher.go
@@ -204,6 +204,26 @@ func (p *DealPublisher) processNewDeal(pdeal *pendingDeal) {
 		return
 	}
 
+	pdealPropCid, err := pdeal.deal.Proposal.Cid()
+	if err != nil {
+		log.Warn("failed to calculate proposal CID for new pending Deal with piece cid %s", pdeal.deal.Proposal.PieceCID)
+		return
+	}
+
+	// Sanity check that new deal isn't already in the queue
+	for _, pd := range p.pending {
+		pdPropCid, err := pd.deal.Proposal.Cid()
+		if err != nil {
+			log.Warn("failed to calculate proposal CID for pending Deal already in publish queue with piece cid %s", pd.deal.Proposal.PieceCID)
+			return
+		}
+
+		if pdPropCid.Equals(pdealPropCid) {
+			log.Warn("tried to process new pending deal with piece CID %s that is already in publish queue; returning", pdeal.deal.Proposal.PieceCID)
+			return
+		}
+	}
+
 	// Add the new deal to the queue
 	p.pending = append(p.pending, pdeal)
 	log.Infof("add deal with piece CID %s to publish deals queue - %d deals in queue (max queue size %d)",