diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index 926161a9b2..e1c1771509 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -375,6 +375,9 @@ Release 0.23.1 - Unreleased
     MAPREDUCE-3604. Fixed streaming to use new mapreduce.framework.name to
     check for local mode. (acmurthy) 
 
+    MAPREDUCE-3521. Fixed streaming to ensure it doesn't silently ignore
+    unknown arguments. (Robert Evans via acmurthy) 
+
 Release 0.23.0 - 2011-11-01 
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-tools/hadoop-streaming/src/main/java/org/apache/hadoop/streaming/StreamJob.java b/hadoop-tools/hadoop-streaming/src/main/java/org/apache/hadoop/streaming/StreamJob.java
index 3a0689d870..39ba36d179 100644
--- a/hadoop-tools/hadoop-streaming/src/main/java/org/apache/hadoop/streaming/StreamJob.java
+++ b/hadoop-tools/hadoop-streaming/src/main/java/org/apache/hadoop/streaming/StreamJob.java
@@ -255,6 +255,13 @@ void parseArgv() {
     }
 
     if (cmdLine != null) {
+      @SuppressWarnings("unchecked")
+      List<String> args = cmdLine.getArgList();
+      if(args != null && args.size() > 0) {
+        fail("Found " + args.size() + " unexpected arguments on the " +
+            "command line " + args);
+      }
+      
       detailedUsage_ = cmdLine.hasOption("info");
       if (cmdLine.hasOption("help") || detailedUsage_) {
         printUsage = true;
diff --git a/hadoop-tools/hadoop-streaming/src/test/java/org/apache/hadoop/streaming/TestStreamJob.java b/hadoop-tools/hadoop-streaming/src/test/java/org/apache/hadoop/streaming/TestStreamJob.java
index 3ba37a845d..3e9036fca9 100644
--- a/hadoop-tools/hadoop-streaming/src/test/java/org/apache/hadoop/streaming/TestStreamJob.java
+++ b/hadoop-tools/hadoop-streaming/src/test/java/org/apache/hadoop/streaming/TestStreamJob.java
@@ -32,7 +32,18 @@
  * This class tests hadoop Streaming's StreamJob class.
  */
 public class TestStreamJob {
-
+  
+  @Test(expected = IllegalArgumentException.class)
+  public void testCreateJobWithExtraArgs() throws IOException {
+    ArrayList<String> dummyArgs = new ArrayList<String>();
+    dummyArgs.add("-input"); dummyArgs.add("dummy");
+    dummyArgs.add("-output"); dummyArgs.add("dummy");
+    dummyArgs.add("-mapper"); dummyArgs.add("dummy");
+    dummyArgs.add("dummy");
+    dummyArgs.add("-reducer"); dummyArgs.add("dummy");
+    StreamJob.createJob(dummyArgs.toArray(new String[] {}));
+  }
+  
   @Test
   public void testCreateJob() throws IOException {
     JobConf job;