Background: We determined the type, symptoms, and risk factors for sleep apnea in heart transplant recipients and the response to nasal continuous positive airway pressure. Methods: A retrospective study on heart transplant recipients with sleep apnea was conducted in a tertiary care medical center with follow-up telephone interviews. Between February 1988 and August 1998, 147 patients underwent orthotopic heart transplantation at our institution. Seventeen patients (11.6%) who were suspected of having sleep apnea underwent polysomnography at a mean interval of 17.5 months after transplantation. Results: All were diagnosed with sleep apnea: 13 had obstructive sleep apnea and 4 had mixed sleep apnea. Mean age at polysomnography was 50.8 years (range, 24-67 years). The patients presented with snoring (100%), excessive daytime somnolence (65%), witnessed apneas (53%), and morning fatigue (53%). Sixteen (94%) had a mean weight gain of 10.4 kg after transplantation, and 1 patient lost 14.6 kg. In the 11 patients with obstructive sleep apnea who underwent nasal continuous positive airway pressure titration, significant improvements occurred in the apnea-hypopnea index (decreased from 37.6 to 10.4; p = 0.01) and mean arousal index (decreased from 44.5 to 19.4; p = 0.01). Only 2 of the 8 patients with sleep apnea for whom nasal continuous positive airway pressure was recommended continued to use it at the time of telephone follow-up. Conclusions: Sleep apnea, especially obstructive sleep apnea, occurs frequently in heart transplant recipients. Obstructive sleep apnea appears to present in the typical manner, and although a positive response to nasal continuous positive airway pressure can be documented by polysomnography, long-term use of nasal continuous positive airway pressure may be low. Copyright (C) 2000 International Society for Heart and Lung Transplantation.