This study is performed to evaluate usefulness of dermal measurement of benzidine and benzidine based dye as one of the occupational exposure assessment method for these compounds. We selected one benzidine manufacturing factory and one dye manufacturing factory in Incheon area. Eleven workers were for benzidine manufacturing factory and twenty four for dye. We analyzed relationships among air level, amount on skin and concentration of urinary metabolites for these compounds. Airborne levels of benzidine and dye were measured by NIOSH 5509, 5013 methods. Amount of these compounds on skin was measured with skin wipe method. Concentration of benzidine metabolites in urine was measured by High Performance Liquid Chromatography after alkaline hydrolysis. The amount of benzidine on hand skin was 25.05( - 233.2) ng/ur, and the amount of the neck was 2.01 ( - 11.9) ng/cm2 in the benzidine dihydrochloride manufacturing factory. The amount of benzidine on hand and neck skin has positive correlation with concentration of urinary monoacetyl benzidine (r=0.644, p < 0.05) . The amount of benzidine based dye on hand skin was 55.75( - 457.7) ng/cm2, and the amount of the neck skin was 18( - 284.7) ng/cm in benzidine based dye manufacturing factory The amount of dye on hand and neck skin has positive correlation with concentration of urinary benzidine for dye workers (r=0.467, p < 0.05). When assessing the exposure of workers who deal with benzidine, the amount of benzidine on skin should be measured for an accurate exposure assessment.