diff --git a/src/main/org/apache/tools/ant/taskdefs/Mkdir.java b/src/main/org/apache/tools/ant/taskdefs/Mkdir.java
index e34e4557d..51fac9ff0 100644
--- a/src/main/org/apache/tools/ant/taskdefs/Mkdir.java
+++ b/src/main/org/apache/tools/ant/taskdefs/Mkdir.java
@@ -74,7 +74,7 @@ public class Mkdir extends Task {
         }
 
         if (dir.isFile()) {
-            log("Warning: Specified directory is a file: " + dir.getAbsolutePath());
+            throw new BuildException("Unable to create directory as a file already exists with that name: " + dir.getAbsolutePath());
         }
 	
         if (!dir.exists()) {