diff --git a/lib/migration.js b/lib/migration.js
index 55182050..57ad4310 100644
--- a/lib/migration.js
+++ b/lib/migration.js
@@ -586,7 +586,7 @@ function mixinMigration(PostgreSQL) {
         }
 
         if (needsToDrop) {
-          sql.push('DROP CONSTRAINT ' + self.escapeName(fk.fkName));
+          sql.push('DROP CONSTRAINT IF EXISTS ' + self.escapeName(fk.fkName));
           removedFks.push(fk); // keep track that we removed these
         }