In this study, we aimed to evaluate the genotoxic effects of fungicides fenarimol and propamocarb which are used to protect crops from fungi. For this reason, bone-marrow micronucleus and chromosome aberration tests were carried out in Swiss albino mice. Mice were injected with four different doses of fenarimol and propamocarb intraperitoneally; 50, 100, 200 and 400 mg/kg b.w. Fenarimol did not induce any significant increase in micronucleated erythrocytes after 24, 36, and 48 h treatment but it decreased the ratio of polychromatic/normochromatic erythrocytes at all dose groups and sampling intervals. Fenarimol did not increase the number of chromosome aberrations significantly, but it reduced the mitotic index at the higher doses (P < 0.05). Propamocarb did not increase the frequency of micronucleated erythrocytes, but decreased the polychromatic/normochromatic erythrocytes ratio at all sampling intervals. Propamocarb increased only gaps in total chromosome aberrations, but when gaps were excluded, there were no significant differences in total aberrations between the control and dose groups (P > 0.05). Propamocarb also reduced the mitotic index compared with the negative control group (P < 0.001). Contributing these results, we can suggest that fenarimol and propamocarb are non-genotoxic in mouse bone marrow in vivo but have cytotoxic effects. (C) 2003 Elsevier Ireland Ltd. All rights reserved.