Adherence to continuous positive airway pressure (CPAP) in patients with sleep apnea hypopnea syndrome (SAHS) is poor. Previous studies have attempted to identify specific barriers to treatment, but none has identified the sole cause for the problem. We outline a behavioral approach to the problem of CPAP adherence that is based on the theories of the transtheoretical model and social cognitive theory. We used these theories to guide the development of an intervention based on the methods of motivational interviewing. We present our motivational enhancement therapy for CPAP (ME-CPAP) here, with some brief pilot data to show its efficacy. Finally, we outline some strengths and weaknesses of taking a behavior change approach to the problem of poor CPAP adherence.