Abstract : We have investigated the role of the occupation and of occupational exposures to petroleum andchlorinated solvents using the data of two epidemiological studies on occupational risk factors ofbreast cancers in men and in women. Unlike female breast cancer (50,000 new cases per year inFrance), cancer of male breast cancer is a rare disease (<500 cases per year). It should be seen asan interesting model for studying the effects of occupational exposures in the disease as theseexposure are generally much higher in men than in women. For men, our results suggest that therisk of cancer is increased among motor vehicle mechanics and support the hypothesis of acarcinogenic effect of solvents such as benzene and trichloroethylene in disease occurrence. Inwomen, several occupations were at increased risk of breast cancer, but results were generallynot statistically significant. No association of female breast cancer incidence with exposure tosolvents was observed.