The present study has been achieved to estimate the acute toxicity effect of pesticide (endosulfan) (organochlorine) and its sublethal concentrations effect  on the oxygen consuming rate of three various snails species (Melanoides tuberculata, Radix auricularia and Theodoxus jordani) collected from Shatt Al-Arab river along the region extended from Abu-Al-Khasib to Garmat-Ali during 2018.  The 24 hr LC50 indicated that the M. tuberculata was more resistant, while R. auricularia and T. jordani were more effective to endosulfan and showed no difference. The study indicated that the employ of various species of snails, with their differing degree of sensitivity to the same toxicant, might be a useful tool in aquatic environmental toxicological investigations. The sublethal concentrations exposure (24 hr LC50) of pesticide had no considerable influence on the rates of oxygen consumption for each snail species. However, a decrease in the capability of snails to preserve respiratory independence through hypoxia was observed 24 hr after exposure to this dose.