In order to encourage corn production, several herbicides such as nicosulfuron and topramezone are used. Though they offer great advantages, they may affect crop productivity and may even induce DNA damage. This study evaluated genotoxic activity at two nicosulfuron concentrations (40,000 and 80, 000 ppm) and at four topramezone concentrations (1480, 148, 14.8 and 1.48 ppm) in sweet corn and hybrid populations from Mexico and South America. NCMAMD were used in 113 variety accessions from Mexico and South America and on 5 commercial hybrids for nicosulfuron and 9 accessions and a hybrid for topramezone. Both nicosulfuron concentrations induced significant genetic damage (P < 0.01) on sweet corn and on normal hybrids. Topramezone showed significant genotoxic activity (P < 0.01) on both sweet corns and normal hybrids. On both sweet corns and normal hybrids, the original situation did not provide protection from genetic damage caused by herbicides and all showed significant genetic damage (P < 0.01) compared to their corresponding negative controls. This paper clearly shows nicosulfuron and topramezone genotoxicity and the study with comet assay in SCAMCN indicated that corn can be used as an excellent biomonitor for genotoxicity assessment.