The determination of urinary beta microglobulin is a sensitive method for screening groups which run the risk of developing renal tubular damage due to cadmium exposure. In this study, the urinary beta microglobulin excretion of 78 male workers who had been exposed to cadmium dust levels of 6.3-11.0 microgram/m from 0.5 to 4 h daily for an average of four years was compared to 35 nonexposed male workers. Possible effects of smoking on renal beta micorglobulin excretion were controlled. The results indicate that the levels of cadmium to which the workers were exposed have no measurable renal effects on the health of workers.