The Academy of Behavioral Medicine Research, the American Psychosomatic Society, the Society for Health Psychology, and the Society of Behavioral Medicine are the four largest behavioral medicine research organizations in North America. All four of these organizations have evolved over the past 40 years, in response to changing times and conditions. They have done so independently, and each one occupies a unique niche in the field of behavioral medicine. However, all four recognize the need for cooperation to address challenges of mutual concern and to capitalize on opportunities for behavioral medicine research to have a greater impact on preventive services and health care. The recent formation of the Behavioral Medicine Research Council (BMRC) is a prime example. As an autonomous joint committee of all four organizations, the BMRC will promote large, definitive, randomized controlled trials to address some of the highest-priority problems in behavioral medicine. This cooperative venture will help the entire field, along with the major behavioral medicine research organizations, continue to evolve in productive ways over the next 40 years.