It's well known that protein/creatinine ratio(P/C ratio) in random urine samples reflects 24-hour urine protein. However, the factors affecting accurate quantitation of proteinuria using random urine P/C ratio are not fully evaluated. The aim of this study is to evaluate factors affecting accurate quantitaion of proteinuria using random urine P/C ratio. 118 patients admitted in Yonsei university medical center during June 1998 and Dec. 1998 were assessed for the measurement of random urine protein/creatinine ratio from second voided urine. 118 patients(mean age 41.5year, male: female 2.36: 1) had mean creati-nine level 1.83±1.78mg/dL, 24-hour pmteinuria 6.06±7.64g/day and P/C ratio 4.80±4.48, All the patiient.s were divided into A, B, C, I, II, K, IV according to serum creatinine level and 24-hour proteinurim amount. The correlation coefficient(R value) between proteinuria and P/C ratio are shown that in all pa- tients is 0.875, group A(Cr≤1.4) 0.884, group B(1A