Chromosome aberrations, micronuclei, and sister chromatid exchanges (SCE) were evaluated in cultured lymphocytes of coke oven workers of an Italian steel industry plant, occupationally exposed to polycyclic aromatic hydrocarbons, and in a group of unexposed controls from a non-oven plant in the same area. No differences were found between exposed and controls for rates of total abnormal metaphases (including and excluding gaps), chromatid-type and chromosome-type aberrations, cells with 2 or more breaks, and for micronuclei. On the contrary, SCE were significantly increased in the exposed versus the controls, but, when smoking habits were considered, the increase was significant only for smokers.