Seven studies examined the validity and usefulness of central constructs in Kohut's self psychology: selfobject needs for mirroring, idealization, and twinship and avoidance of acknowledging these needs. These constructs were assessed with a new self-report measure that was found to be reliable, valid, and empirically linked with a variety of constructs in contemporary personality and social psychology. The findings supported and refined Kohut's ideas about the independence of the 3 selfobject needs, the orthogonality between these needs and defensive attempts to avoid acknowledging them, the motivational bases of narcissism, and the contribution of selfobject needs to problems in interpersonal functioning, mental health, self-cohesion, and affect regulation. The findings reveal mutually beneficial conceptual links between Kohut's self psychology and attachment theory and suggest ways in which Kohut's theory can be studied empirically.