Calypso (thiacloprid), Poncho (clothianidin), Gaucho (imidacloprid), and Jade (imidacloprid) are commercial neonicotinoid insecticides, a new class of agrochemicals in México. However, genotoxic and cytotoxic studies have not been performed. In the present study, human peripheral blood lymphocytes (PBL) were exposedin vitroto different concentrations of the four insecticides. The genotoxic and cytotoxic effects were evaluated using the alkaline comet and trypan blue dye exclusion assays. DNA damage was evaluated using two genotoxicity parameters: tail length and comet frequency. Exposure to9.5×10-6to5.7×10-5 M Jade;2.8×10-4to1.7×10-3 M Gaucho;0.6×10-1to1.4×10-1 M Calypso;1.2×10-1to9.5×10-1 M Poncho for 2 h induced a significant increase DNA damage with a concentration-dependent relationship. Jade was the most genotoxic of the four insecticides studied. Cytotoxicity was observed in cells exposed to18×10-3 M Jade,2.0×10-3 M Gaucho,2.0×10-1 M Calypso, 1.07 M Poncho, and cell death occurred at30×10-3 M Jade,3.3×10-3 M Gaucho,2.8×10-1 M Calypso, and 1.42 M Poncho. This study provides the first report of genotoxic and cytotoxic effects in PBL followingin vitroexposure to commercial neonicotinoid insecticides.