diff --git a/src/main/org/apache/tools/ant/PropertyHelper.java b/src/main/org/apache/tools/ant/PropertyHelper.java
index 6026b32b8..c5feac93b 100644
--- a/src/main/org/apache/tools/ant/PropertyHelper.java
+++ b/src/main/org/apache/tools/ant/PropertyHelper.java
@@ -369,7 +369,9 @@ public class PropertyHelper {
 
         project.log("Setting project property: " + name + " -> " +
                 value, Project.MSG_DEBUG);
-        properties.put(name, value);
+        if( name!= null && value!=null ) {
+            properties.put(name, value);
+        }
     }
 
     /**