diff --git a/hibernate-core/src/main/java/org/hibernate/cfg/annotations/PropertyBinder.java b/hibernate-core/src/main/java/org/hibernate/cfg/annotations/PropertyBinder.java
index 02be4376ad..cfdd6874b9 100644
--- a/hibernate-core/src/main/java/org/hibernate/cfg/annotations/PropertyBinder.java
+++ b/hibernate-core/src/main/java/org/hibernate/cfg/annotations/PropertyBinder.java
@@ -284,12 +284,10 @@ public class PropertyBinder {
 				prop.setGeneration( PropertyGeneration.parse( generated.toString().toLowerCase() ) );
 			}
 		}
-		NaturalId naturalId = property != null ?
-				property.getAnnotation( NaturalId.class ) :
-				null;
+		NaturalId naturalId = property != null ? property.getAnnotation( NaturalId.class ) : null;
 		if ( naturalId != null ) {
 			NaturalIdMutability mutability = naturalId.mutability();
-			if ( mutability == null ) {
+			if ( mutability == NaturalIdMutability.UNSPECIFIED ) {
 				mutability = naturalId.mutable()
 						? NaturalIdMutability.MUTABLE
 						: NaturalIdMutability.IMMUTABLE_CHECKED;
diff --git a/hibernate-core/src/main/java/org/hibernate/mapping/Property.java b/hibernate-core/src/main/java/org/hibernate/mapping/Property.java
index 9ebb3bd5b8..96f7236db2 100644
--- a/hibernate-core/src/main/java/org/hibernate/mapping/Property.java
+++ b/hibernate-core/src/main/java/org/hibernate/mapping/Property.java
@@ -150,10 +150,12 @@ public class Property implements Serializable, MetaAttributable {
 		// if the property mapping consists of all formulas, 
 		// make it non-updateable
 		final boolean[] columnUpdateability = value.getColumnUpdateability();
-		return updateable && ( 
-				//columnUpdateability.length==0 ||
-				!ArrayHelper.isAllFalse(columnUpdateability)
-			);
+		final boolean isImmutableNaturalId = isNaturalIdentifier()
+				&& ( NaturalIdMutability.IMMUTABLE.equals( getNaturalIdMutability() )
+						|| NaturalIdMutability.IMMUTABLE_CHECKED.equals( getNaturalIdMutability() ) );
+		return updateable
+				&& !isImmutableNaturalId
+				&& !ArrayHelper.isAllFalse(columnUpdateability);
 	}
 
 	public boolean isInsertable() {
@@ -174,7 +176,8 @@ public class Property implements Serializable, MetaAttributable {
         this.generation = generation;
     }
 
-    public void setUpdateable(boolean mutable) {
+    public void setUpdateable(
+			boolean mutable) {
 		this.updateable = mutable;
 	}
 
@@ -324,4 +327,5 @@ public class Property implements Serializable, MetaAttributable {
 	public void setNaturalIdMutability(NaturalIdMutability naturalIdMutability) {
 		this.naturalIdMutability = naturalIdMutability;
 	}
+
 }
diff --git a/hibernate-core/src/main/java/org/hibernate/tuple/entity/EntityMetamodel.java b/hibernate-core/src/main/java/org/hibernate/tuple/entity/EntityMetamodel.java
index 55ff479de3..2e0f7d304f 100644
--- a/hibernate-core/src/main/java/org/hibernate/tuple/entity/EntityMetamodel.java
+++ b/hibernate-core/src/main/java/org/hibernate/tuple/entity/EntityMetamodel.java
@@ -37,6 +37,7 @@ import org.jboss.logging.Logger;
 import org.hibernate.EntityMode;
 import org.hibernate.HibernateException;
 import org.hibernate.MappingException;
+import org.hibernate.NaturalIdMutability;
 import org.hibernate.engine.OptimisticLockStyle;
 import org.hibernate.engine.internal.Versioning;
 import org.hibernate.engine.spi.CascadeStyle;
@@ -154,7 +155,7 @@ public class EntityMetamodel implements Serializable {
 
 		propertySpan = persistentClass.getPropertyClosureSpan();
 		properties = new StandardProperty[propertySpan];
-		List naturalIdNumbers = new ArrayList();
+		List<Integer> naturalIdNumbers = new ArrayList<Integer>();
 		// temporary ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 		propertyNames = new String[propertySpan];
 		propertyTypes = new Type[propertySpan];
@@ -195,7 +196,7 @@ public class EntityMetamodel implements Serializable {
 
 			if ( prop.isNaturalIdentifier() ) {
 				naturalIdNumbers.add( i );
-				if ( prop.isUpdateable() ) {
+				if ( prop.isUpdateable() && NaturalIdMutability.MUTABLE.equals( prop.getNaturalIdMutability() ) ) {
 					foundUpdateableNaturalIdProperty = true;
 				}
 			}