Pesticides which constitute an group of environmental pollutants are commonly used in agriculture to protect crops. Pesticide exposure may be associated with increased risk of genotoxicity and carcinogenesis. Therefore, they pose a potential risk to farmers and environment. The aim of the present study is to investigate whether occupational exposure to various pesticides causes Chromosomal Aberrations (CAs) in agricultural farmers. The frequency of CAs in peripheral blood lymphocytes were evaluated in 35 Agricultural Farmers (AFs) and 40 control subjects living in Çukurova Region. The results showed that farmers exposed to pesticides had signifi cantly increased frequencies of CAs when compared with controls (P<0.05). Ageadjusted group comparisons showed that the frequency of CAs in the pesticide exposed AFs were 2,3 times higher than in the control group (OR: 2,3, 95% wald confi dence limits: 1,9-2,9). The confounding factors such as variable duration of pesticide exposure, age, smoking, alcohol consumption had no signifi cant effect on cytogenetic damage (P>0.05). Fragile sites (FSs) on the 1(q21-24), 1(q31-32), 2(q31-34), 2(q21-23), 3(p21), 3(p25) and 5(q31-q34) chromosomal regions were signifi cantly overexpressed in AFs, when compared to the control group (in 12.6% versus 4.3% of cells) (P<0.05). Our fi ndings indicate that occupational exposure to pesticides could cause cytogenetic damage in somatic cells of AFs. It is known that accumulation of CAs is a crucial step for initiation of many cancers. Therefore, it is suggested that the exposed workers should be warned about the potential harmful effects of pesticides and relevant authorities should safeguard that protective measures are taken by farmers while working in agricultural fi elds.