organophosphates are widely used in agriculture as pesticides, in industry and as household chemicals, allowing many opportunities for acute poisoning, as well as for occupational use. Besides, organophosphates being nerve agents are used in military setting or in terrorist attacks. Fifty years after first use, we still do not know what the optimum treatment for organophosphate toxicity is. Small studies suggest benefit from new treatments such as magnesium sulphate, but much larger trials are needed. The aim of the study was to evaluate the effect of i.v. Magnesium sulphate on mortality rate in acute organophosphate toxicity. Patients and methods: a comparative study in which iv magnesium sulphate was given in a dose of 1g/6hrs for 24hrs to 50 patients acutely intoxicated with organophosphate who are treated with atropine and oximes (group i) and compared to 50 patients who are not given iv magnesium sulphate who are treated with atropine and oximes then mortality rate in the two groups are compared. Results: comparison between the control and the group which took magnesium sulphate showed a statistical significant difference between the 2 groups in the mortality rate (p<0.05). Conclusion: magnesium sulphate decreases mortality rate in acute organophosphate toxicity .such information may in turn guide clinical practice to the use of magnesium sulphate in acute organophosphate toxicity and so more studies should be done to confirm these findings