This paper, part of a series exploring the development of Freud's object concept, deals with the concepts of objects and psychic structure in the period from 1915 to 1938. In connection with the increased prominence of object loss and hostility in his clinical material, the role of objects in the building of psychic structure via identification assumed increased importance from 1917 on. After introduction of the ego-id-superego model, Freud asserted for the first time that object choice does take place as early as the oedipal period, and interpolated the phallic-oedipal phase into his sequence of developmental phases. The prominence of structure formation through identification continued, but no new object concepts are discerned.