diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index 292a42b2de3..5f034c8ed05 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -159,6 +159,9 @@ Branch-2 ( Unreleased changes )
     MAPREDUCE-3906. Fix inconsistency in documentation regarding
     mapreduce.jobhistory.principal. (Eugene Koontz via harsh)
 
+    MAPREDUCE-4422. YARN_APPLICATION_CLASSPATH needs a documented default
+    value in YarnConfiguration. (Ahmed Radwan via harsh)
+
   OPTIMIZATIONS
 
   BUG FIXES
diff --git a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
index 26ef90d894c..6f2c11f1331 100644
--- a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
+++ b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
@@ -541,10 +541,25 @@ public class YarnConfiguration extends Configuration {
   public static final long DEFAULT_NM_PROCESS_KILL_WAIT_MS =
       2000;
 
-  /** Standard Hadoop classes */
+  /**
+   * CLASSPATH for YARN applications. A comma-separated list of CLASSPATH
+   * entries
+   */
   public static final String YARN_APPLICATION_CLASSPATH = YARN_PREFIX
       + "application.classpath";
 
+  /**
+   * Default CLASSPATH for YARN applications. A comma-separated list of
+   * CLASSPATH entries
+   */
+  public static final String DEFAULT_YARN_APPLICATION_CLASSPATH =
+    "$HADOOP_CONF_DIR," + "$HADOOP_COMMON_HOME/share/hadoop/common/*," +
+    "$HADOOP_COMMON_HOME/share/hadoop/common/lib/*," +
+    "$HADOOP_HDFS_HOME/share/hadoop/hdfs/*," +
+    "$HADOOP_HDFS_HOME/share/hadoop/hdfs/lib/*," +
+    "$YARN_HOME/share/hadoop/mapreduce/*," +
+    "$YARN_HOME/share/hadoop/mapreduce/lib/*";
+
   /** Container temp directory */
   public static final String DEFAULT_CONTAINER_TEMP_DIR = "./tmp";
 
diff --git a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
index 6e8df109dd4..ba570c3e5df 100644
--- a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
+++ b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
@@ -538,16 +538,9 @@
   </property>
 
   <property>
-    <description>Classpath for typical applications.</description>
+    <description>CLASSPATH for YARN applications. A comma-separated list
+    of CLASSPATH entries</description>
      <name>yarn.application.classpath</name>
-     <value>
-        $HADOOP_CONF_DIR,
-        $HADOOP_COMMON_HOME/share/hadoop/common/*,
-        $HADOOP_COMMON_HOME/share/hadoop/common/lib/*,
-        $HADOOP_HDFS_HOME/share/hadoop/hdfs/*,
-        $HADOOP_HDFS_HOME/share/hadoop/hdfs/lib/*,
-        $YARN_HOME/share/hadoop/mapreduce/*,
-        $YARN_HOME/share/hadoop/mapreduce/lib/*
-     </value>
+     <value>$HADOOP_CONF_DIR,$HADOOP_COMMON_HOME/share/hadoop/common/*,$HADOOP_COMMON_HOME/share/hadoop/common/lib/*,$HADOOP_HDFS_HOME/share/hadoop/hdfs/*,$HADOOP_HDFS_HOME/share/hadoop/hdfs/lib/*,$YARN_HOME/share/hadoop/mapreduce/*,$YARN_HOME/share/hadoop/mapreduce/lib/*</value>
   </property>
 </configuration>