For the screening of genotoxicity of pesticides various plant materials has been used as test material but common onion(Allium cepa) and garlic(Allium sativum) is an excellent plant for the biomonitoring of pesticides. The increase use of pesticides in agricultural field as well as in house pest control raise a question of interest that these pesticides causes any cytological damage or not. To screen out the effect of the pesticides the Allium test is a common and routinely used method. The mitotic and meiotic both the studies of Allium are held for the assessment of genotoxicity of pesticides. The inhibition in mitotic index and induction in chromosomal aberrations by the treatment of pesticides are the parameter of assessment of toxicity.