The authors undertook this study to determine changes in the daily concentration of cadmium, copper, and zinc in Japanese workers' urine over a 13-year period from 1985 to 1998. The workers were aged between 20 and 59 years. The authors studied 277 subjects in 1985, 320 in 1993, and 292 in 1998, for a total of 889 (464 men and 425 women). Although. in both men and women, urinary excretions of cadmium and copper were lower in 1993 and 1998 than in 1985, they were not substantially lower in 1998 than in 1993. The authors observed no marked changes between 1985, 1993, and 1998 regarding the excretion of zinc in any of the age groups in either men or women. Furthermore, the excretion of urinary cadmium in 1998 still exceeded the tolerable limit levels in the general population of the investigated region in Japan. This fact suggests the necessity of further nationwide investigation and comprehensive measures to reduce cadmium exposure in Japanese society.