diff --git a/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/AnnotationPersistenceMetaDataParser.java b/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/AnnotationPersistenceMetaDataParser.java
index a35b5f89c..ce5b478f9 100644
--- a/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/AnnotationPersistenceMetaDataParser.java
+++ b/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/AnnotationPersistenceMetaDataParser.java
@@ -599,8 +599,13 @@ public class AnnotationPersistenceMetaDataParser
                         warnFlushMode(meta);
                     break;
                 case ID_CLASS:
-                    if (isMetaDataMode())
+                    if (isMetaDataMode()) {
+                    	Class<?> idClass = ((IdClass)anno).value();
+                    	if (!Serializable.class.isAssignableFrom(idClass)) {
+                    		_log.warn(_loc.get("id-class-not-serializable", idClass, _cls).toString());
+                    	}
                         meta.setObjectIdType(((IdClass) anno).value(), true);
+                    }
                     break;
                 case NATIVE_QUERIES:
                     if (isQueryMode() && (meta.getSourceMode() & MODE_QUERY)==0)
diff --git a/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/XMLPersistenceMetaDataParser.java b/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/XMLPersistenceMetaDataParser.java
index 3dc65495f..84974c807 100644
--- a/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/XMLPersistenceMetaDataParser.java
+++ b/openjpa-persistence/src/main/java/org/apache/openjpa/persistence/XMLPersistenceMetaDataParser.java
@@ -21,6 +21,7 @@ package org.apache.openjpa.persistence;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.Serializable;
 import java.lang.reflect.Field;
 import java.lang.reflect.Member;
 import java.lang.reflect.Method;
@@ -1266,6 +1267,9 @@ public class XMLPersistenceMetaDataParser
         } catch (Throwable t) {
             throw getException(_loc.get("invalid-id-class", meta, cls), t);
         }
+        if (!Serializable.class.isAssignableFrom(idCls)) {
+        	_conf.getConfigurationLog().warn(_loc.get("id-class-not-serializable", idCls, _cls));
+        }
         meta.setObjectIdType(idCls, true);
         return true;
     }
diff --git a/openjpa-persistence/src/main/resources/org/apache/openjpa/persistence/localizer.properties b/openjpa-persistence/src/main/resources/org/apache/openjpa/persistence/localizer.properties
index 41550d046..a963b490b 100644
--- a/openjpa-persistence/src/main/resources/org/apache/openjpa/persistence/localizer.properties
+++ b/openjpa-persistence/src/main/resources/org/apache/openjpa/persistence/localizer.properties
@@ -256,3 +256,4 @@ EntityManagers this property should not be used because these EntityManagers may
 time.
 shared-cache-mode-take-precedence: The DataCache is set to {0} while the shared-cache-mode Element or \
 javax.persistence.sharedCache.mode property is set to NONE. The shared-cache-mode takes precedence and caching is disabled.
+id-class-not-serializable: The composite identity class "{0}" for entity "{1}" is not serializable.
\ No newline at end of file