Abstract: It has been suggested that urinary retinal-binding protein(RBP)and (β₂-microglobulin (β₂-MG) excretion are very useful marker of proximal tubular defunction.To evaluate the relationship between RBP and β₂-M Gin urine and proximal tubular impairment.The RBP and β₂-MG levels in urine from 208 cancer patients were determined with RIA and ELISA separately. The results showed that the levels of RBP and β₂-MG are significantly higher than control group. The positive rate of RBP and R2一MG is 62.50%and 62.02%respectively(P>0.05).The content of RBP in urine is less affected by extrarenal factor, RBP is more stable in urine than β₂-MG, also the method detecting RBP is simpler than those of β₂-MG.So we recommend that RBP may be more useful marker in diagnoseing the proximal tubular impairment in cancer patients.We condude that urinary RBP concentration can reflect the degree of renal damage in cancer patients sensitively.