Abstract Data from the large-scale biological monitoring program in Japan were assembled and analyzed and the following results were obtained. All workers handling lead and eight kinds of major organic solvents received physical examinations and biological monitoring at the same time. Therefore, the number of workers handling industrial chemicals and that received physical examinations and the number of workers been examined by biological monitorings were similar to each other. The total number of cases examined from 1989 to 1994 was about 661 000 for lead in the blood and about 4173000 for the urinary metabolites of eight organic solvents. The results were classified into three categories and category 3 consists of workers having exposure concentrations above the 1988–1989 biological exposure indices of the ACGIH with the exception of lead concentration in the blood where the limit in Japan was set at 40 μg/100 ml. The percentage of exposed workers in category 3 was 1.4% for blood lead and 0.2–2.4% for the urinary metabolites of the eight organic solvents. The percentage of exposed workers in category 3 for blood lead, δ-aminolevulinic acid, urinary mandelic acid, N-methylformamide and 2,5-hexanedione in the urine has decreased with time. In ambient monitoring, the percentage of workplaces in classification 3 for lead and styrene also has decreased with time.