Obstructive sleep apnea is a chronic disease whose treatment may require long-term nightly use of relatively cumbersome and expensive breathing equipment that provides continuous positive airway pressure (CPAP) via nasal mask. Compliance with this treatment may be influenced not only by the objective improvement in sleep apnea but also by the patient's subjective perception of the benefit, bed mate or family support, side effects, and cost. The last factor may not be important in Ontario, where 75% of the cost is paid by the Ministry of Health. The goal of this study was to analyze the factors that may influence patient acceptance of nasal CPAP. This was done by tabulating the responses to a detailed questionnaire mailed to 148 patients with obstructive sleep apnea (OSA). There were 96 replies. We were able to contact by telephone an additional 42 patients. The results showed that 105 patients continued to use CPAP at a mean follow-up time of 17 ± 11 months, some for as long as 6 yr. The majority of patients (81%) perceived CPAP as an effective treatment of the disorder, 5% were unsure, and 14% believed that CPAP was ineffective, despite the resolution of sleep apnea on polysomnography. Subjective improvement reported by the patients was also observed by the family members in 83% of the patients. The most common complaint, voiced by 46% of the patients, was nocturnal awakenings. Nasal problems, such as dryness, congestion, and sneezing, were the second most frequent complaint present in 44% of the responders. Of the 96 patients who completed the questionnaire, 17 returned nasal CPAP after an average of 3 ± 4 months of use, resulting in a compliance rate of 82%, similar to previous studies conducted in patient populations without government-sponsored insurance programs. The noncompliant patients did not differ in the severity of apnea or response to treatment from those who kept the equipment, but a significantly greater proportion did not perceive any beneficial effects, their families did not notice any improvement, and these patients voiced significantly more adverse comments about the CPAP equipment than those who kept it. We conclude that although many patients report adverse side effects of CPAP, the compliance with this treatment is relatively high and a large majority of patients (81%) believe that the treatment is beneficial. We further conclude that essentially cost-free access to home CPAP equipment does not improve the compliance over that previously reported in the literature.