diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index e24658e4d4..65b2d9d330 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -384,6 +384,9 @@ Release 0.23.3 - UNRELEASED
     MAPREDUCE-4129. Lots of unneeded counters log messages (Ahmed Radwan via
     bobby)
 
+    MAPREDUCE-3947. yarn.app.mapreduce.am.resource.mb not documented 
+    (Devaraj K via bobby)
+
 Release 0.23.2 - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/resources/mapred-default.xml b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/resources/mapred-default.xml
index b62259039a..a60bc3ed46 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/resources/mapred-default.xml
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/resources/mapred-default.xml
@@ -1257,6 +1257,12 @@
     throwing exception. This is a layer above the ipc.</description>
 </property>
 
+<property>
+  <name>yarn.app.mapreduce.am.resource.mb</name>
+  <value>2048</value>
+  <description>The amount of memory the MR AppMaster needs.</description>
+</property>
+
 <!-- jobhistory properties -->
 
 <property>