Objective. The aim of this study was to investigate demographic, clinical and psychosocial factors associated with sleep quality in patients on continuous ambulatory peritoneal dialysis (CAPD). Material and methods. Demographic data, clinical and biochemical parameters of 112 CAPD patients (convenience sample of 52 women and 60 men, mean age 51 +/- 15 years) were measured. In the same patients, the Pittsburgh Sleep Quality Index (PSQI) was used for assessing sleep quality, the Beck Depression Inventory (BDI) for severity of depressive symptoms, the International Restless Legs Syndrome Study Group criteria for the diagnosis of restless legs syndrome (RLS), and the Short Form-36 (SF-36) of Medical Outcomes Study questionnaire for quality of life (QoL). Results. Patients with PSQI scores of > 5 ("bad sleepers") had lower serum albumin (p = 0.008), total cholesterol (p = 0.034), normalized protein equivalent of nitrogen appearance (p = 0.046) and residual renal function (p = 0.012), but higher serum ferritin (p = 0.016) and BDI scores (p < 0.001). No significant correlation could be demonstrated between sleep quality and other demographic and clinical parameters. Although the prevalence of RLS was higher in poor sleepers, the difference did not reach statistical significance (p = 0.067). In multivariate analysis, only elevated BDI was an independent predictor of poor sleep quality (p = 0.031). Compared with good sleepers, poor sleepers had significantly lower QoL scores in all subscales of the SF-36. Conclusions. Although poor sleepers had lower nutritional indices, an elevated BDI was the only independent predictor of poor sleep quality. Poor sleep quality was also associated with lower QoL in patients on CAPD.