To evaluate the performance of a lead-surveillance program in reducing blood lead levels of workers in Taiwan, the authors conducted prospective and cross-sectional studies. A total of 6 905 workers, whose job titles indicated a direct exposure to lead in 1995, were included in this surveillance system. In this study, the authors compared the mean blood lead levels in 1994 (i.e., year of onset of surveillance) with that in 1995 in workers of major industries. Lead-exposed workers had a statistically significant decrease (i.e., average of 1.8 microg/dl) in blood lead levels during this 1-y period. The decrease was particularly obvious in individuals who worked in chemical products manufacturing, ship building/repairing, and plastic products manufacturing. The significant decreases in blood lead levels in these workers indicated that this surveillance system was effective. Surveillance, combined with control measures, might be an important means by which occupational lead exposure can be reduced.