Four male obese patients with obstructive sleep apnea were evaluated by polysomnography, both prior and 3-4 months following gastroplasty. The surgery was performed as an alternative weight loss treatment. These patients were selected for gastroplasty because they had severe obesity, obstructive sleep apnea with cardiopulmonary impairment and noncompliance on a weight loss diet. Tracheostomy was performed concomitantly in three cases. Preoperative recording demonstrated 21.2 to 100.3 apneas per hour of sleep; stage 3 was decreased in three and absent in one case; stage 4 was absent in every patient; stage REM was decreased in three cases; arterial oxygen saturation (Sa0(2)) was below 80% in every case during apenas. Follow-up recordings with occluded tracheostomy were obtained 3-4 months after surgery. The weight reduction varied from 16.3 to 41.4% of the initial weight. The recording documented normal sleep apnea indices in three cases and partial recovery in the remainder; increase in stages 3, 4 and REM; normal Sa0(2) in three out of 4 cases. These findings suggest that gastroplasty may be used as an alternative treatment for weight reduction in selected OSA patients.