Using PDC test, peritoneal function in CAPD patients was compared between diabetes and non- diabetes. PDC test were performed in 12 diabetic and 11 nondiabetic CAPD patients. Urea, creatinine, and albumin were measured in each dialysate effluent. Blood urea nitrogen, creatinine, glucose, albumin, and sodium were measured in blood sample at the start and the end of the study. Area parameter(Ao/d x), hydraulic conductance(LpS), final absorption rate (JVAR), large pore fluid flux(JVr.), urea generation rate(UGR), creatinine generation rate (CGR), protein nitrogen appearance/protein catabolic rate(PNA/PCR), residual renal Ccr, total Ccr(PD Ccr+renal Ccr), water removal via PD, total ultrafiltration, and PD clearance of urea, creatinine, vitamin B12 b2 microglobulin, and albumin were calculated. In diabetic patients(n=12), serum albumin was lower in patients on CAPD for less 6 months than patients on CAPD for more 15 months. But total ultrafiltration was lower in patients on CAPD for more 15 months. In non-diabetics(n=ll), protein loss across the peritoneum was lower in patients on CAPD for more 15 months. Other PDC parameters were not different in diabetic and non-diabetic patients according to CAPD duration. In patients on CAPD for less 6 months, serum albumin and PNA/PCR were lower in diabetics than non-diabetics.