Patients with end-stage renal failure (ESRF) are reported to have a high prevalence of sleep disorders, such as daytime sleepiness, insomnia, restless legs syndrome (RLS), and obstructive sleep apnea syndrome (OSAS). However, there are few published data from Southeast Asia. A sleep questionnaire was administered to 201 patients (103 men) at the continuous ambulatory peritoneal dialysis (CAPD) outpatient clinic to assess sleep problems. Patients had a mean age of 56.7 +/- 12 (SD) years, with a mean body mass index (BMI) of 23.6 +/- 3.5 kg/m(2). Daytime sleepiness was the most frequent symptom (77.1%), and frequent awakening occurred in 69% of the patients. Sleep-onset insomnia and sleep-maintenance insomnia occurred in 73% and 60% of the patients, respectively. Sixty-two percent of the patients reported symptoms of RLS, which significantly correlated with sleep-onset insomnia (odds ratio [OR], 2.9; 95% confidence interval [CI], 1.5 to 5.5; P = 0.001) and sleep-maintenance insomnia (OR, 2.1; 95% CI, 1.2 to 3.8; P = 0.014). The prevalence of OSAS was estimated by the frequency of the following symptoms: extremely loud snoring, 7 patients (3.5%); observed choking, 21 patients (10.5%); witnessed apnea, 11 patients (5.6%); snoring and witnessed apnea, 6 patients (3%); disruptive snoring, 29 patients (14.4%); and disruptive snoring and witnessed apnea, 3 patients (1.5%). This questionnaire survey confirmed a high prevalence of daytime sleepiness, insomnia, and RLS in patients with ESRF undergoing CAPD but showed a relatively low prevalence of OSAS of up to 14.4%, which may be related to the low BMI of these patients with ESRF compared with other populations. Whether this contributes to the overall better survival observed in some Asian patients with ESRF undergoing dialysis needs further investigation.