diff --git a/hibernate-core/src/main/java/org/hibernate/engine/spi/CollectionEntry.java b/hibernate-core/src/main/java/org/hibernate/engine/spi/CollectionEntry.java
index 01d9ccd05e..fcd269acba 100644
--- a/hibernate-core/src/main/java/org/hibernate/engine/spi/CollectionEntry.java
+++ b/hibernate-core/src/main/java/org/hibernate/engine/spi/CollectionEntry.java
@@ -264,6 +264,20 @@ public final class CollectionEntry implements Serializable {
 		return snapshot;
 	}
 
+	/**
+	 * Reset the stored snapshot for both the persistent collection and this collection entry. 
+	 * Used during the merge of detached collections.
+	 * 
+	 * @param collection the persistentcollection to be updated
+	 * @param storedSnapshot the new stored snapshot
+	 */
+	public void resetStoredSnapshot(PersistentCollection collection, Serializable storedSnapshot) {
+		LOG.debugf("Reset storedSnapshot to %s for %s", storedSnapshot, this);
+		
+		snapshot = storedSnapshot;
+		collection.setSnapshot(loadedKey, role, snapshot);
+	}
+
 	private void setLoadedPersister(CollectionPersister persister) {
 		loadedPersister = persister;
 		setRole( persister == null ? null : persister.getRole() );
@@ -422,4 +436,4 @@ public final class CollectionEntry implements Serializable {
 		        ( session == null ? null : session.getFactory() )
 		);
 	}
-}
\ No newline at end of file
+}
diff --git a/hibernate-core/src/main/java/org/hibernate/type/CollectionType.java b/hibernate-core/src/main/java/org/hibernate/type/CollectionType.java
index f7683161de..ebd9884734 100644
--- a/hibernate-core/src/main/java/org/hibernate/type/CollectionType.java
+++ b/hibernate-core/src/main/java/org/hibernate/type/CollectionType.java
@@ -29,9 +29,12 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.SortedMap;
+import java.util.TreeMap;
 
 import org.dom4j.Element;
 import org.dom4j.Node;
@@ -40,6 +43,7 @@ import org.hibernate.Hibernate;
 import org.hibernate.HibernateException;
 import org.hibernate.MappingException;
 import org.hibernate.collection.spi.PersistentCollection;
+import org.hibernate.engine.spi.CollectionEntry;
 import org.hibernate.engine.spi.CollectionKey;
 import org.hibernate.engine.spi.EntityEntry;
 import org.hibernate.engine.spi.Mapping;
@@ -49,6 +53,7 @@ import org.hibernate.engine.spi.SessionImplementor;
 import org.hibernate.internal.CoreMessageLogger;
 import org.hibernate.internal.util.MarkerObject;
 import org.hibernate.internal.util.collections.ArrayHelper;
+import org.hibernate.internal.util.collections.CollectionHelper;
 import org.hibernate.metamodel.relational.Size;
 import org.hibernate.persister.collection.CollectionPersister;
 import org.hibernate.persister.collection.QueryableCollection;
@@ -512,12 +517,73 @@ public abstract class CollectionType extends AbstractType implements Association
 				if ( ! ( ( PersistentCollection ) original ).isDirty() ) {
 					( ( PersistentCollection ) result ).clearDirty();
 				}
+
+				if (elemType instanceof AssociationType) {
+					preserveSnapshot(( PersistentCollection )original, ( PersistentCollection ) result, (AssociationType) elemType, owner, copyCache, session);
+				}
 			}
 		}
 
 		return result;
 	}
 
+	private void preserveSnapshot(PersistentCollection original ,PersistentCollection result, AssociationType elemType, Object owner,
+			Map copyCache, SessionImplementor session) {
+		Serializable originalSnapshot = original.getStoredSnapshot();
+		Serializable resultSnapshot = result.getStoredSnapshot();
+		Serializable targetSnapshot;
+		
+		if (originalSnapshot instanceof List) {
+			targetSnapshot = new ArrayList(((List) originalSnapshot).size()); 
+			for (Object obj : (List) originalSnapshot) {
+				((List) targetSnapshot).add(elemType.replace(obj, null, session, owner, copyCache));
+			}
+		
+		} else if (originalSnapshot instanceof Map) {
+			if (originalSnapshot instanceof SortedMap) {
+				targetSnapshot = new TreeMap(((SortedMap) originalSnapshot).comparator());
+			} else {
+				targetSnapshot = new HashMap(
+						CollectionHelper.determineProperSizing( ((Map) originalSnapshot).size()), 
+						CollectionHelper.LOAD_FACTOR);
+			}
+			
+			for (Map.Entry<Object, Object> entry : ((Map<Object,Object>) originalSnapshot).entrySet()) {
+				Object key = entry.getKey();
+				Object value = entry.getValue();
+				Object resultSnapshotValue = (resultSnapshot == null) ? null : ((Map<Object,Object>) resultSnapshot).get(key);
+				
+				if (key == value) { 
+					Object newValue = elemType.replace(value, resultSnapshotValue, session, owner, copyCache );
+					((Map) targetSnapshot).put(newValue, newValue);
+						
+				} else {
+					Object newValue = elemType.replace(value, resultSnapshotValue, session, owner, copyCache );
+					((Map) targetSnapshot).put(key, newValue);
+				}
+				
+			}
+
+		} else if (originalSnapshot instanceof Object []) {
+			Object [] arr = ( Object []) originalSnapshot;
+			for (int i=0; i< arr.length; i++) {
+				arr[i] = elemType.replace(arr[i], null, session, owner, copyCache );
+			}
+			targetSnapshot = originalSnapshot;
+		
+		} else {
+			// retain the same snapshot
+			targetSnapshot = resultSnapshot;
+			
+		}
+		
+		CollectionEntry ce = session.getPersistenceContext().getCollectionEntry(result);
+		if (ce != null) {
+			ce.resetStoredSnapshot(result, targetSnapshot);
+		}
+		
+	}
+
 	/**
 	 * Instantiate a new "underlying" collection exhibiting the same capacity
 	 * charactersitcs and the passed "original".