A study was performed to evaluate the efficacy of dry biomass from the microalgae Nannochloropsis oculata and Spirogyra porticalis in removing insecticides from water, such as fenamiphos, imidacloprid, and oxamyl. Pesticide dissipation was studied based on incubation time, pesticide concentration, and algal biomass concentration. Analyzing and quantifying pesticides through UV-Vis spectrophotometry was validated. For fenamiphos, optimum conditions were 15 minutes, 50 mg/l pesticide concentration, and 900 mg/L algal biomass with responses 68.67 and 67.27% by N. oculata and S. porticalis, respectively. The optimum conditions for imidacloprid were 15 min, 50 mg/L pesticide concentration, and 900 mg/L algal biomass, with responses of 35.55 and 28.20% by N. oculata and S. porticalis, respectively. In the same conditions, the responses were 81.31 % and 65.71 % for oxamyl by N. oculata and S. porticalis, respectively. This study proved that the microalgae N. oculata and S. porticalis were both active and biomass dependent in their ability to remove insecticides. As a result, the insecticides levels in the water samples that were tainted appeared to be potentially reduced by these algae biomass.