Serum total amylase, pancreatic amylase and lipase activities were studied prospectively in 43 hemodialysis, 22 peritoneal dialysis and 22 chronic renal failure patients. None of the patients had symptoms of pancreatic disease at the time of study. Mean total amylase activities were similar and above the upper limit of normal in the 3 treatment groups. Total amylase was abnormal in 75% of the patients and exceeded twice the upper limit of normal in 24%. Blacks and nondiabetics had higher levels than whites and diabetic patients, respectively. Percentage pancreatic amylase exceeded the upper limits of normal in one third of the patients. Mean pancreatic amylase was above the upper normal limit in the 3 groups, and values were abnormal in 63% of all patients. Mean pancreatic amylase activity was significantly lower in peritoneal dialysis than in hemodialysis or chronic renal failure patients (p = 0.01). Pancreatic amylase activity was unaffected by race. The higher total amylase activity in blacks was due to increased salivary isoenzyme. Hemodialysis treatments did not change total amylase or pancreatic amylase activity. Mean lipase activity approximated the upper limit of normal in the 3 groups and values were abnormal in 42 % of all patients. Serum total amylase and pancreatic amylase activity did not increase during episodes of peritonitis in the peritoneal dialysis group. Peritoneal dialysis, whether or not accompanied by peritonitis, was responsible for removal of only a small amount of amylase activity per day. The results indicate that reference values for serum amylases must be adjusted not only for the presence of chronic renal failure, but also for the type of therapy employed, the patients’ race and the presence or absence of diabete