The arsenic exposure in the main departments and occupational groups of the copper smelter in Pirdop has been estimated in the present study. The contents of arsenic is measured in the air and in biological samples--urine and nails. At most of the workplaces the time-weighted average (TWA) concentrations do not exceed the threshold limit value (0.05 mg/m3). The maximum TWA level is about three times higher. The intake of arsenic is significantly increased in almost all observed occupational groups. However, the excretion of only 8% of the workers is higher than the maximum background level (100 micrograms/l). The estimated degree of exposure corresponds to a low health risk. Some of the most heavily exposed occupational groups may be expected to reach higher levels of intake and health risk.