diff --git a/source/org/jivesoftware/smack/packet/Packet.java b/source/org/jivesoftware/smack/packet/Packet.java
index d33d3ebc1..35ef94ad4 100644
--- a/source/org/jivesoftware/smack/packet/Packet.java
+++ b/source/org/jivesoftware/smack/packet/Packet.java
@@ -206,6 +206,11 @@ public abstract class Packet {
      * class to handle custom parsing. In that case, the type of the Object
      * will be determined by the provider.
      *
+     * <p>Note: According to the XMPP specification, IQ packets cannot contain
+     * packet extensions. Instead, they must contain only a single XML sub-document,
+     * which is returned via the {@link IQ#getChildElementXML()} method. Therefore,
+     * attempting to add an extension to an IQ packet will silently fail.
+     *
      * @param elementName the XML element name of the packet extension.
      * @param namespace the XML element namespace of the packet extension.
      * @return the extension, or <tt>null</tt> if it doesn't exist.
@@ -226,9 +231,19 @@ public abstract class Packet {
     /**
      * Adds a packet extension to the packet.
      *
+     * <p>Note: According to the XMPP specification, IQ packets cannot contain
+     * packet extensions. Instead, they must contain only a single XML sub-document,
+     * which is returned via the {@link IQ#getChildElementXML()} method. Therefore,
+     * attempting to add an extension to an IQ packet will silently fail.
+     *
      * @param extension a packet extension.
      */
     public synchronized void addExtension(PacketExtension extension) {
+        // If the packet is an IQ packet, ignore trying to add an extension to it.
+        if (this instanceof IQ) {
+            return;
+        }
+
         if (packetExtensions == null) {
             packetExtensions = new ArrayList();
         }
@@ -238,6 +253,11 @@ public abstract class Packet {
     /**
      * Removes a packet extension from the packet.
      *
+     * <p>Note: According to the XMPP specification, IQ packets cannot contain
+     * packet extensions. Instead, they must contain only a single XML sub-document,
+     * which is returned via the {@link IQ#getChildElementXML()} method. Therefore,
+     * attempting to add an extension to an IQ packet will silently fail.
+     *
      * @param extension the packet extension to remove.
      */
     public synchronized void removeExtension(PacketExtension extension)  {