The research was targeted to investigate the effect of nano-TiO 2 (anatase) on germination, vigour index, stress enzymes and mitotic cell cycle profile in lentils ( Lens culinaris Medik.). Seed germination results indicated that TiO 2 NP (Nanoparticle) at lowest concentration promotes seed germination, vigour index and biomass; however, at higher concentrations, they showed significant reduction in growth parameters and photosynthetic pigments in concentration-dependent manner. NP treatments triggered an excessive formation of reactive oxygen species (ROS) which was evident from increased production of stress enzymes, lipid peroxidation, augmented DNA damage and aberrant mitotic cell division. The results exhibit a dose-dependent modification of NP- mediated oxidative stress and genotoxicity in lentil.