The relationship between urinary cadmium concentration expressed as microgram/g creatinine and renal effects of cadmium exposure was studied in 542 inhabitants over 20 years of age who lived in the Jinzu River basin which is polluted by cadmium. Cadmium concentration in urine was employed as the index of cadmium exposure. Total protein with glucose, beta 2-microglobulin, retinol binding protein, and proline served as indices of renal effects. The prevalent rate of high beta 2-microglobulin excretion was the highest among these indices both in men and women. Prevalence rates of indices of renal effects increased proportionally with increasing cadmium concentrations in urine and probit linear regression lines could be calculated between them. The urinary cadmium concentrations corresponding to 1% prevalence rates of indices of the renal effects were calculated by the regression line. For beta 2-microglobulin, 3.2 microgram Cd/g creatinine and 5.2 microgram Cd/g creatinine were obtained in men and women, respectively. This method may be useful for evaluating the risk of renal damage of exposed inhabitants.