diff --git a/pulp/pulp.py b/pulp/pulp.py
index a05a964f..e1cade69 100644
--- a/pulp/pulp.py
+++ b/pulp/pulp.py
@@ -555,6 +555,8 @@ def infeasibilityGap(self, mip=1):
         return 0
 
     def isBinary(self):
+        if self.cat == const.LpBinary:
+            return True
         return self.cat == const.LpInteger and self.lowBound == 0 and self.upBound == 1
 
     def isInteger(self):