During the time period from 1984 to 1988, blood cadmium concentration decreased by 56% in 31 males who were not occupationally exposed to cadmium and who lived in a Belgian urban area where there existed nonferrous industries. A 40% decrease in blood cadmium concentration was also observed in an independent cross-sectional survey conducted in 1985 and 1988 among 412 subjects who lived in a rural area. This latter decrease persisted when the main determinants of blood cadmium concentration--gender, age, and tobacco--were allowed for. The results presented are consistent with a decrease in environmental cadmium exposure in Belgium.