ABSTRACT. – Synthetic aminophosphates are a class of organophosphorus compounds commonly used for protecting crops, however, the toxic effects on terrestrial and aquatic non-target organisms limit their uses. Freshwater protozoan ciliate, Paramecium tetraurelia was used as an alternative cellular model to evaluate the cytotoxic effects of aminophosphates. The present study was therefore, aimed to compare the toxic effects of two newly synthesized aminophosphates (Ap1 at 30 & 60mM and Ap2 at 40 & 60mM) and glyphosate (0.66mM), a commercialized pesticide in Algeria, on growth and major cellular antioxidant makers (GSGSH, GSGST, and CAT) in Paramecium tetraurelia. The median lethal concentration (LC50) values of Ap1, Ap2, and glyphosate were preliminarily determined. The test chemicals caused marked disruption in Paramecium kinetic growth and the cellular behavior including the trajectory and motility velocity and decreased percentage of response. In addition, the GSGSH level, and the enzymatic activity of GAT and GSGST were significantly decreased in treated cells. The observed adverse effects were less pronounced in Ap1 and Ap2 as compared with glyphosate-treated cells. Conclusively, the Ap1 and Ap2 proved to be promising lesser toxic and safer compounds than glyphosate on protozoan ciliate, Paramecium tetraurelia.