diff --git a/src/main/org/apache/tools/ant/taskdefs/ExecTask.java b/src/main/org/apache/tools/ant/taskdefs/ExecTask.java
index 60a51f44c..0a4fcaaae 100644
--- a/src/main/org/apache/tools/ant/taskdefs/ExecTask.java
+++ b/src/main/org/apache/tools/ant/taskdefs/ExecTask.java
@@ -170,6 +170,12 @@ public class ExecTask extends Task {
         if (cmdl.getExecutable() == null) {
             throw new BuildException("no executable specified", location);
         }
+        if (dir != null && !dir.exists()) {
+        	throw new BuildException("The directory you specified does not exist");
+        }
+        if (dir != null && !dir.isDirectory()) {
+        	throw new BuildException("The directory you specified is not a directory");
+        }
     }
 
     /**