This paper examines dominant sources of social power and influence that affect the degree to which patients adhere to recommended regimens for prevention or treatment and their rate of recovery. Referent power of health‐care practitioners, as contrasted with their expert, coercive, reward and legitimate power, is expected to be most effective when internalization of medical recommendations by the patients is essential. The paper explores specific ways that a health‐care professional can gain referent power, using weight control treatment as an example. It presents a conceptual framework that provides a rationale for a number of relationship‐building techniques and offers evidence that referent power is effective in promoting adherence to treatment and more healthful behavior, and in influencing critical outcome measures such as weight loss. Analysis of the relative efficacy of various methods of building and using referent power and the possible limiting conditions on its effectiveness are also disc