Protein-calorie malnutrition is common in CAPD patients and is associated with increase in morbidity and mortality in CAPD patients. There are many causes of malnutrition in CAPD patients, and it is well known that a large amount of protein losses through peritoneal membrane is one of them. To investigate the effect of the peritoneal membrane transport characteristics on the nutritional status in long-term CAPD patients, we conducted a cross- sectional study on clinically stable 115 patients(63 males and 52 females) who have been on CAPD for more than 2 years, and assessed nutritional status by subjective global assessment(SGA), biochemical, anthropometric and urea kinetic parameters. Patients were divided into 4 groups according to the results of standard peritoneal equilibration test(PET). The results were as follows: 1) The patients were divided into 4 groups according to the PET results: high transporter(n=16, 14%), high average transporter(n=38, 33%), low average transporter(n=50, 43%), and low transporter (n=11, 10%). 2) The mean age of the patients was 50.1±11.6 years(range, 19-75) with sex ratio(M:F) 1.2:1 and mean duration of dialysis was 57.5±27.8 months (range, 24-135). The mean body weight(Bwt) was 59.2±8.9kg, percent ideal body weight(%IBW) was 104.7±15.6%, %lean body mass(LBM)/Bwt was 82.1±11.1%, and malnourished patients by subjective global assessment(SGA) were 32.2%(38/115). 3) The mean BUN, creatinine, total protein, and albumin level of the patients were 54.5±13.1mg/dL, 12.3±3.0mg/dL, 6.7±0.8g/dL, and 3.8±0.6g/dL, respectively. 4) There were no significant differences in age, sex ratio, CAPD duration, peritonitis rate, %LBM/ Bwt, and SGA among the 4 groups. 5) Total protein(g/dL) and albumin(g/dL) levels in high transporters were 6.4±0.5, 3.5±0.4, respectively, and they were significantly lower than those of low transporters(7.2±0.6, 4.2±0.5)(P<0.05). 6) 24 hour dialysate protein(g/day) and albumin (g/day) losses were significantly higher in high transporters(8.10±1.85, 4.19±1.23) compared to those of low transporters(5.07±1.85, 2.78±0.99)(P<0.05). 7) The level of IGF-1(ng/mL) was significantly lower in high transporters (150.5±86.2) compared to that of low transporters(310.3±162.1)(P<0.05). 8) The level of BUN(mg/dL), Cr(mg/dL) were also lower in high transporters(45.4±13.1, 10.1±2.0) than those of low transporters(61.6±18, 14.7±2.7), but there were no significant differences in Hct, total cholesterol, prealbumin, and transferrin among the 4 groups. 9) There were no statistically significant differences in Kt/Vurea, RRF, NPCR, dietary calorie and protein intakes among the 4 groups. 10) Anthrometric parameters such as TSF, BSF, MAC and LBM measured by three different methods (LBMCr, LBMimp, LBManthro) didn't show any significant differences among the 4 groups. In conclusion, increased peritoneal permeability may not adversely affect SGA and anthropometric status of long-term CAPD patients, although it is associated with lower serum albumin, creatinine, and IGF-1 level. Clinical significance of these findings remains to be elucidated.