It is well known that depression and sense of hopelessness worsen the quality of life in end-stage renal disease (ESRD) patients receiving dialysis. However, the characteristics of depression in continuous ambulatory peritoneal dialysis (CAPD) patients have not been analyzed in detail. We performed this study to investigate the severity of depression and the factors affecting depression in CAPD patients. With 96 CAPD patients, we evaluated each patient's depressive mood and hopelessness with CES-D (Center for Epidemiologic Studies Depression) scale and Beck Hopelessness Scale. We also evaluated the degree of stress of each patient with internal individual stress scale. Most CAPD patients experienced severe depression compared with the general population. Their depression was better explained by psychological factors, such as stress and sense of hopelessness, than by demographic or physical factors. On the basis of these findings, we suggest that the treatment of depression in CAPD patients might be possible by modulation of psychological factors.