diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 20ecf86753..a1420bd3be 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -336,6 +336,9 @@ Branch-2 ( Unreleased changes )
     HDFS-3531. EditLogFileOutputStream#preallocate should check for
     incomplete writes. (Colin Patrick McCabe via eli)
 
+    HDFS-766. Error message not clear for set space quota out of boundary
+    values. (Jon Zuanich via atm)
+
   BREAKDOWN OF HDFS-3042 SUBTASKS
 
     HDFS-2185. HDFS portion of ZK-based FailoverController (todd)
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/DFSAdmin.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/DFSAdmin.java
index c7c206fcb7..211220803e 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/DFSAdmin.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/DFSAdmin.java
@@ -239,7 +239,12 @@ private static class SetSpaceQuotaCommand extends DFSAdminCommand {
       CommandFormat c = new CommandFormat(2, Integer.MAX_VALUE);
       List<String> parameters = c.parse(args, pos);
       String str = parameters.remove(0).trim();
-      quota = StringUtils.TraditionalBinaryPrefix.string2long(str);
+      try {
+        quota = StringUtils.TraditionalBinaryPrefix.string2long(str);
+      } catch (NumberFormatException nfe) {
+        throw new IllegalArgumentException("\"" + str + "\" is not a valid value for a quota.");
+      }
+      
       this.args = parameters.toArray(new String[parameters.size()]);
     }
     
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/resources/testHDFSConf.xml b/hadoop-hdfs-project/hadoop-hdfs/src/test/resources/testHDFSConf.xml
index 918c004516..1f6a6265ff 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/resources/testHDFSConf.xml
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/resources/testHDFSConf.xml
@@ -15470,7 +15470,7 @@
       <comparators>
         <comparator>
           <type>SubstringComparator</type>
-          <expected-output>For input string: "a5"</expected-output>
+          <expected-output>setSpaceQuota: "a5" is not a valid value for a quota.</expected-output>
         </comparator>
       </comparators>
     </test>