Few studies investigating the effects of automated peritoneal dialysis (APD) and continuous ambulatory peritoneal dialysis (CAPD) on health-related quality of life (HRQoL), depression, and sleep quality exist in the literature. We aimed to determine differences between APD and CAPD modalities with respect to these parameters. Twenty APD and 48 CAPD patients were included in this cross-sectional study. Biochemical values were measured at outpatient evaluation. A modified postsleep inventory was used to evaluate sleep quality. Health-related quality of life and depression were evaluated by the Short Form of Medical Outcomes Study and Beck Depression Inventory, respectively. Automated peritoneal dialysis and CAPD patients were compared in terms of sleep quality, HRQoL, and depression. Our results showed that there were no significant differences between APD and CAPD in any of the studied parameters. Moderate or severe sleep problems were found in 60% and 69% of the APD and CAPD patients, respectively. Mean HRQoL scores for any of the 8 Short Form of Medical Outcomes Study-36 domains were similar in the 2 groups. The mean physical component score was 51.1 ± 21.2 and 48.9 ± 18.2 in APD and CAPD patients, respectively (P=0.672). The mean mental component score was 47.5 ± 20.1 in APD patients, whereas it was 42.4 ± 19.5 in CAPD patients (P=0.291). Depression was detected in 70% of APD and 62.5% of the CAPD patients. The mean Beck Depression Inventory scores were also similar in the 2 groups. This study showed that HRQoL, sleep quality, and depression were similar in APD and CAPD patients. © 2010 The Authors. Hemodialysis International © 2010 International Society for Hemodialysis.