diff --git a/src/java/org/apache/poi/ss/formula/functions/BooleanFunction.java b/src/java/org/apache/poi/ss/formula/functions/BooleanFunction.java
index 5b5b539fe..9c50e2a1a 100644
--- a/src/java/org/apache/poi/ss/formula/functions/BooleanFunction.java
+++ b/src/java/org/apache/poi/ss/formula/functions/BooleanFunction.java
@@ -94,7 +94,7 @@ public abstract class BooleanFunction implements Function,ArrayFunction {
             }
 			
 			if (arg == MissingArgEval.instance) {
-				tempVe = null;		// you can leave out parameters, they are simply ignored
+				tempVe = false;		// missing parameters are treated as FALSE
 			} else {
 				tempVe = OperandResolver.coerceValueToBoolean(arg, false);
 			}