Though traditionally recognized as being of central importance in the psychotherapeutic process, the therapist-patient relationship has remained shadowy and ill defined. Behavior therapy, derived as it is from behavior-theory principles, offers potentially fruitful leads to attaining a clearer understanding of the critical variables involved. The relationship, operationally defined in social reinforcement terms and conceived of as an integral aspect of more basic social behavior-influence methods, is systematically used to achieve well-defined predetermined therapeutic goals. The applicability and means of maximizing the efficiency of this therapeutic method are discussed.