Serum markers of visceral and somatic protein status are directly correlated with the survival of hemodialysis patients. We prospectively examined the relationship of single baseline levels of serum albumin, cholesterol, creatinine, and urea to prognosis in 80 continuous ambulatory peritoneal dialysis patients monitored for up to 33 months. Other variables tested included age, race, gender, diabetes, cause of end-stage renal disease, and number of months on dialysis. The Cox proportional hazards model was used to determine independent predictors of mortality risk. In a subgroup of 33 patients followed for up to 21 months, the predictive value of single measurements of baseline serum prealbumin also was tested. Overall, 29 patients died during the study. Independent predictors of mortality risk included serum albumin (P = 0.024) and creatinine (P = 0.006), diabetes (P < 0.06), prior months on dialysis (P < 0.05), and older age (P = 0.18). In a subgroup of 33 patients with prealbumin measurements, there were nine deaths over 21 months. A serum prealbumin level less than 30 mg/dL was associated with an increased mortality rate compared with higher prealbumin values (odds ratio, 3.8; P = 0.09). We conclude that markers of visceral and somatic nutrition are important and independent predictors of mortality risk in continuous ambulatory peritoneal dialysis patients. We are unable to suggest whether the relationship is causal or causative. However, the predictive value of these single baseline markers were valid for up to 33 months. We also note that patients with diabetes are at an increased risk even after adjusting for somatic and visceral protein status.