Hi, Since Hibernate 3.2 is not possible to use the same column as discriminator and primary key. I could do it in previous versions of hibernate. This is the stacktrace I get: Caused by: org.hibernate.MappingException: Repeated column in mapping for entity: ar.com.refert.sil.bo.Child column: ident (should be mapped with insert="false" update="false") at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:647) at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:690) at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:445) at org.hibernate.mapping.SingleTableSubclass.validate(SingleTableSubclass.java:43) at org.hibernate.cfg.Configuration.validate(Configuration.java:1102) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1287) Here is the code: Parent class: @Entity @Inheritance(strategy=InheritanceType.SINGLE_TABLE) @DiscriminatorColumn(name="ident",discriminatorType=DiscriminatorType.INTEGER) @DiscriminatorValue("1") public class Parent { private Long id; @Id public Long getIdent() { return id; } public void setIdent(Long id) { this.id = id; } } Child Class: @Entity @DiscriminatorValue("2") public class Child extends Parent { } Thanks, -- Pablo Nussembaum Refert