diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index f31639ff180..857f11e6604 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -133,6 +133,8 @@ Release 0.23.3 - UNRELEASED
     HADOOP-8169.  javadoc generation fails with java.lang.OutOfMemoryError:
     Java heap space (tgraves via bobby)
 
+    HADOOP-8167. Configuration deprecation logic breaks backwards compatibility (tucu)
+
   BREAKDOWN OF HADOOP-7454 SUBTASKS
 
     HADOOP-7455. HA: Introduce HA Service Protocol Interface. (suresh)
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java
index c98ff1ece10..44bb72318e3 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/conf/Configuration.java
@@ -306,7 +306,26 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
   private static boolean isDeprecated(String key) {
     return deprecatedKeyMap.containsKey(key);
   }
- 
+
+  /**
+   * Returns the alternate name for a key if the property name is deprecated
+   * or if deprecates a property name.
+   *
+   * @param name property name.
+   * @return alternate name.
+   */
+  private String getAlternateName(String name) {
+    String altName;
+    DeprecatedKeyInfo keyInfo = deprecatedKeyMap.get(name);
+    if (keyInfo != null) {
+      altName = (keyInfo.newKeys.length > 0) ? keyInfo.newKeys[0] : null;
+    }
+    else {
+      altName = reverseDeprecatedKeyMap.get(name);
+    }
+    return altName;
+  }
+
   /**
    * Checks for the presence of the property <code>name</code> in the
    * deprecation map. Returns the first of the list of new keys if present
@@ -619,8 +638,8 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
 
   /** 
    * Set the <code>value</code> of the <code>name</code> property. If 
-   * <code>name</code> is deprecated, it sets the <code>value</code> to the keys
-   * that replace the deprecated key.
+   * <code>name</code> is deprecated or there is a deprecated name associated to it,
+   * it sets the value to both names.
    * 
    * @param name property name.
    * @param value property value.
@@ -629,18 +648,17 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
     if (deprecatedKeyMap.isEmpty()) {
       getProps();
     }
-    if (!isDeprecated(name)) {
-      getOverlay().setProperty(name, value);
-      getProps().setProperty(name, value);
-      updatingResource.put(name, UNKNOWN_RESOURCE);
+    getOverlay().setProperty(name, value);
+    getProps().setProperty(name, value);
+    updatingResource.put(name, UNKNOWN_RESOURCE);
+    String altName = getAlternateName(name);
+    if (altName != null) {
+      getOverlay().setProperty(altName, value);
+      getProps().setProperty(altName, value);
     }
-    else {
+    if (isDeprecated(name)) {
       DeprecatedKeyInfo keyInfo = deprecatedKeyMap.get(name);
       LOG.warn(keyInfo.getWarningMessage(name));
-      for (String newKey : keyInfo.newKeys) {
-        getOverlay().setProperty(newKey, value);
-        getProps().setProperty(newKey, value);
-      }
     }
   }
   
@@ -648,10 +666,13 @@ public class Configuration implements Iterable<Map.Entry<String,String>>,
    * Unset a previously set property.
    */
   public synchronized void unset(String name) {
-    name = handleDeprecation(name);
-
+    String altName = getAlternateName(name);
     getOverlay().remove(name);
     getProps().remove(name);
+    if (altName !=null) {
+      getOverlay().remove(altName);
+       getProps().remove(altName);
+    }
   }
 
   /**
diff --git a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/conf/TestConfigurationDeprecation.java b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/conf/TestConfigurationDeprecation.java
index a6f95ef097e..e5a7748d5cf 100644
--- a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/conf/TestConfigurationDeprecation.java
+++ b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/conf/TestConfigurationDeprecation.java
@@ -20,6 +20,7 @@ package org.apache.hadoop.conf;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
@@ -27,6 +28,7 @@ import java.io.BufferedWriter;
 import java.io.File;
 import java.io.FileWriter;
 import java.io.IOException;
+import java.util.Map;
 
 import org.apache.hadoop.fs.Path;
 import org.junit.After;
@@ -270,4 +272,56 @@ public class TestConfigurationDeprecation {
         new String[]{ "tests.fake-default.new-key" });
     assertEquals("hello", conf.get("tests.fake-default.new-key"));
   }
+
+  @Test
+  public void testIteratorWithDeprecatedKeys() {
+    Configuration conf = new Configuration();
+    Configuration.addDeprecation("dK", new String[]{"nK"});
+    conf.set("k", "v");
+    conf.set("dK", "V");
+    assertEquals("V", conf.get("dK"));
+    assertEquals("V", conf.get("nK"));
+    conf.set("nK", "VV");
+    assertEquals("VV", conf.get("dK"));
+    assertEquals("VV", conf.get("nK"));
+    boolean kFound = false;
+    boolean dKFound = false;
+    boolean nKFound = false;
+    for (Map.Entry<String, String> entry : conf) {
+      if (entry.getKey().equals("k")) {
+        assertEquals("v", entry.getValue());
+        kFound = true;
+      }
+      if (entry.getKey().equals("dK")) {
+        assertEquals("VV", entry.getValue());
+        dKFound = true;
+      }
+      if (entry.getKey().equals("nK")) {
+        assertEquals("VV", entry.getValue());
+        nKFound = true;
+      }
+    }
+    assertTrue("regular Key not found", kFound);
+    assertTrue("deprecated Key not found", dKFound);
+    assertTrue("new Key not found", nKFound);
+  }
+
+  @Test
+  public void testUnsetWithDeprecatedKeys() {
+    Configuration conf = new Configuration();
+    Configuration.addDeprecation("dK", new String[]{"nK"});
+    conf.set("nK", "VV");
+    assertEquals("VV", conf.get("dK"));
+    assertEquals("VV", conf.get("nK"));
+    conf.unset("dK");
+    assertNull(conf.get("dK"));
+    assertNull(conf.get("nK"));
+    conf.set("nK", "VV");
+    assertEquals("VV", conf.get("dK"));
+    assertEquals("VV", conf.get("nK"));
+    conf.unset("nK");
+    assertNull(conf.get("dK"));
+    assertNull(conf.get("nK"));
+  }
+
 }