Pesticides are widely used throughout the world in agriculture to protect crops and in public health to control diseases. Nevertheless exposure to pesticides can represent a potential risk to humans. Pesticide manufacturing unit workers are prone to possible occupational pesticide exposure. Therefore, this study was performed to evaluate the genotoxic effect of pesticide exposure in these workers. In the present investigation 54 pesticide workers and an equal number of control subjects were assessed for genome damage in blood lymphocytes utilizing the chromosomal aberration analysis and the buccal epithelial cell by adopting the micronucleus test. The results suggested that pesticide workers had a significantly increased frequency of chromosomal aberrations when compared with controls (mean+/-S.D., 8.43+/-2.36 versus 3.32+/-1.26; P<0.05). Similarly, the pesticides exposed workers showed a significant increase in micronucleated cells compared with controls (1.24+/-0.72 versus 0.32+/-0.26; P<0.05). Analysis of variance revealed that occupational exposure to pesticides had a significant effect on frequency of micronuclei (P<0.05), whereas smoking, age, gender and alcohol consumption had no significant effect on genetic damage (P>0.05). However, no association was found between years of exposure, smoking, age, gender, alcohol consumption and higher levels of genetic damage as assessed by the chromosomal aberration assay (P>0.05). Our findings indicate that occupational exposure to pesticides could cause genome damage in somatic cells.