To determine long-term compliance rates to continuous positive airway pressure (CPAP) therapy in patients with obstructive sleep apnea enrolled in a comprehensive CPAP program in the community. Prospective cohort longitudinal study. University sleep disorders center. Two hundred ninety-six patients with an apnea-hypopnea index (AHI) > or = 20/h on polysomnography. A CPAP device equipped with a monitoring chip was supplied. Within the first week, daily telephone contacts were made. Patients were seen at 2 weeks, 4 weeks, 3 months, and 6 months. Of the 296 subjects enrolled, 81.1% were males. Mean +/- SD AHI was 64.4 +/- 34.2/h of sleep; age, 51 +/- 11.7 years; and body mass index, 35.2 +/- 7.9 kg/m(2). The mean duration of CPAP use was 5.7 h/d at 2 weeks, 5.7 h/d at 4 weeks, 5.9 h/d at 3 months, and 5.8 h/d at 6 months. The percentage of patients using CPAP > or = 3.5 h/d was 89.0% at 2 weeks, 86.6% at 4 weeks, 88.6% at 3 months, and 88.5% at 6 months. There was a decrease in the Epworth Sleepiness Scale (ESS) score of 44% by 2 weeks of therapy. The patients continue to improve over the follow-up period, with the lowest mean ESS score observed at 6 months. With multiple regression analysis, three variables were found to be significantly correlated with increased CPAP use: female gender, increasing age, and reduction in ESS score. A population-based CPAP program consisting of consistent follow-up, "troubleshooting," and regular feedback to both patients and physicians can achieve CPAP compliance rates of > 85% over 6 months.