PURPOSE: Hyperglycemia, hypoalbuminemia and other factors make diabetic CRF patient vulnerable to salt and fluid retention, which is partial explanation of high mortality rate of DM dialysis patients. This prospective study was carried out to investigate the different membrane characteristics associated with ultrafiltration between diabetic and non diabetic CAPD patients. METHODS: Among new CAPD patients from May 2001 to January 2004 in our hospitals, 60 patients who had complete data more than 12 month were enrolled. Peritoneal equilibration test and D/P1hr Na using 4.25% dialysate, daily ultrafiltration and urine volume, serum albumin and glucose level, daily exposed and daily absorbed glucose amount through the peritoneal cavity and clinical indices were measured at 1st, 6th, and 12th months after initiation of CAPD. We analyzed data with independent t test, repeated measure of ANOVA and multiple regression by STATA. RESULTS: We can summarized the RESULTS: Changes of body weight, total body water, daily ultrafiltration volume (UFV), D/P4Cr, UFV during PET and RRF were not significantly different between DM and non-DM at 1st, 6th, and 12th months. But 1st month serum albumin was lower in DM (p=0.01). Daily exposed glucose amount was significantly higher in DM group at 1st and 12th months (161.7+/-44.5 g/day vs. 140.3+/-21.1 g/day and 157.4+/-43.8 g/ day vs. 134.0+/-11.3 g/day, p=0.019, p=0.006, respectively). At 1st month, D/P1hr Na was not significantly different between DM and non-DM but DM group showed getting higher (D/P)1hr Na at 6th and 12th month (p=0.04, p=0.006, respectively). Factors associated with D/P1hr Na were DM (beta-coeff= -0.015, p=0.042), log hs CRP (beta-coeff=0.012, p= 0.025), 24 hours dialysate albumin (beta-coeff=-0.010, p=0.000), and D/P4Cr (beta-coeff=0.150, p=0.000). CONCLUSION: Diabetic CAPD patients showed more rapid increase of D/P1hr Na during initial 1 year. It might be due to more rapid deterioration of water channel function with time on PD. In terms of achieving adequate ultrafiltration in diabetic peritoneal dialysis patient with time, higher concentration of glucose or icodextrin containing dialysate might be needed to overcome decreased water channel function.