diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index 4ca2ce31ee..44df787ed4 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -476,6 +476,9 @@ Branch-2 ( Unreleased changes )
     HADOOP-8749. HADOOP-8031 changed the way in which relative xincludes are handled in 
     Configuration. (ahmed via tucu)
 
+    HADOOP-8431. Running distcp wo args throws IllegalArgumentException.
+    (Sandy Ryza via eli)
+
   BREAKDOWN OF HDFS-3042 SUBTASKS
 
     HADOOP-8220. ZKFailoverController doesn't handle failure to become active
diff --git a/hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/DistCp.java b/hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/DistCp.java
index 416847b821..e507c7a8c5 100644
--- a/hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/DistCp.java
+++ b/hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/DistCp.java
@@ -98,6 +98,11 @@ private DistCp() {}
    * @return On success, it returns 0. Else, -1.
    */
   public int run(String[] argv) {
+    if (argv.length < 1) {
+      OptionsParser.usage();
+      return DistCpConstants.INVALID_ARGUMENT;
+    }
+    
     try {
       inputOptions = (OptionsParser.parse(argv));