There have been several major theories proposed to account for the development of stereotypes of old people. The literature on stereotyping of the elderly is reviewed, with an emphasis on the attitudes of various health workers, especially physicians and psychiatrists. The theories and supporting data of the classical psychoanalytic theory, psychodynamic theories, cognitive dissonance theory, status inconsistency theory, attribution theory, labeling theory, and Marxian social science theory are critiqued. The congruence among these theories is examined and the interactions between different frameworks discussed. The implications of this unified hypothesis focus on its impact on the delivery of health care services to the elderly. The self-fulfilling prophecy of stereotyping reinforces both the theories and the stereotypic behavior of old persons. Stereotype elimination requires societal restructuring and the creation of meaningful roles for the elderly. (Author/LS)