Weight loss is a frequently recommended treatment for obese patients with obstructive sleep apnea (OSA). The empirical support for this recommendation is lacking. Based on descriptive studies, weight loss appears to improve but not abolish sleep disordered breathing. Moreover, the degree of improvement in OSA is quite variable and not directly proportional to weight loss. The lack of randomized trials, the study of predominantly male samples, and the absence of follow-up evaluations leave physicians and patients unsure about the utility of weight loss treatment in obese OSA patients.