diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index e0ad4237944..a6ace4c3380 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -128,6 +128,9 @@ Release 2.5.0 - UNRELEASED
     MAPREDUCE-5924. Changed TaskAttemptImpl to ignore TA_COMMIT_PENDING event
     at COMMIT_PENDING state. (Zhijie Shen via jianhe)
 
+    MAPREDUCE-5939. StartTime showing up as the epoch time in JHS UI after
+    upgrade (Chen He via jlowe)
+
 Release 2.4.1 - 2014-06-23 
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/main/java/org/apache/hadoop/mapreduce/v2/jobhistory/FileNameIndexUtils.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/main/java/org/apache/hadoop/mapreduce/v2/jobhistory/FileNameIndexUtils.java
index 54bbcd93c52..741da11b4ae 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/main/java/org/apache/hadoop/mapreduce/v2/jobhistory/FileNameIndexUtils.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/main/java/org/apache/hadoop/mapreduce/v2/jobhistory/FileNameIndexUtils.java
@@ -168,10 +168,14 @@ public class FileNameIndexUtils {
           decodeJobHistoryFileName(jobDetails[QUEUE_NAME_INDEX]));
 
       try{
-        indexInfo.setJobStartTime(
-          Long.parseLong(decodeJobHistoryFileName(jobDetails[JOB_START_TIME_INDEX])));
+        if (jobDetails.length <= JOB_START_TIME_INDEX) {
+          indexInfo.setJobStartTime(indexInfo.getSubmitTime());
+        } else {
+          indexInfo.setJobStartTime(
+              Long.parseLong(decodeJobHistoryFileName(jobDetails[JOB_START_TIME_INDEX])));
+        }
       } catch (NumberFormatException e){
-        LOG.warn("Unable to parse launch time from job history file "
+        LOG.warn("Unable to parse start time from job history file "
             + jhFileName + " : " + e);
       }
     } catch (IndexOutOfBoundsException e) {
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/test/java/org/apache/hadoop/mapreduce/v2/jobhistory/TestFileNameIndexUtils.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/test/java/org/apache/hadoop/mapreduce/v2/jobhistory/TestFileNameIndexUtils.java
index 015c87ad7f5..a0d5fceb35e 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/test/java/org/apache/hadoop/mapreduce/v2/jobhistory/TestFileNameIndexUtils.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-common/src/test/java/org/apache/hadoop/mapreduce/v2/jobhistory/TestFileNameIndexUtils.java
@@ -39,6 +39,17 @@ public class TestFileNameIndexUtils {
     + FileNameIndexUtils.DELIMITER + "%s"
     + JobHistoryUtils.JOB_HISTORY_FILE_EXTENSION;
 
+  private static final String OLD_FORMAT_BEFORE_ADD_START_TIME = "%s"
+      + FileNameIndexUtils.DELIMITER + "%s"
+      + FileNameIndexUtils.DELIMITER + "%s"
+      + FileNameIndexUtils.DELIMITER + "%s"
+      + FileNameIndexUtils.DELIMITER + "%s"
+      + FileNameIndexUtils.DELIMITER + "%s"
+      + FileNameIndexUtils.DELIMITER + "%s"
+      + FileNameIndexUtils.DELIMITER + "%s"
+      + FileNameIndexUtils.DELIMITER + "%s"
+      + JobHistoryUtils.JOB_HISTORY_FILE_EXTENSION;
+
   private static final String JOB_HISTORY_FILE_FORMATTER = "%s"
     + FileNameIndexUtils.DELIMITER + "%s"
     + FileNameIndexUtils.DELIMITER + "%s"
@@ -235,6 +246,22 @@ public class TestFileNameIndexUtils {
         QUEUE_NAME_WITH_DELIMITER, info.getQueueName());
   }
 
+  @Test
+  public void testJobStartTimeBackwardsCompatible() throws IOException{
+    String jobHistoryFile = String.format(OLD_FORMAT_BEFORE_ADD_START_TIME,
+        JOB_ID,
+        SUBMIT_TIME,
+        USER_NAME,
+        JOB_NAME_WITH_DELIMITER_ESCAPE,
+        FINISH_TIME,
+        NUM_MAPS,
+        NUM_REDUCES,
+        JOB_STATUS,
+        QUEUE_NAME );
+    JobIndexInfo info = FileNameIndexUtils.getIndexInfo(jobHistoryFile);
+    Assert.assertEquals(info.getJobStartTime(), info.getSubmitTime());
+  }
+
   @Test
   public void testJobHistoryFileNameBackwardsCompatible() throws IOException {
     JobID oldJobId = JobID.forName(JOB_ID);