Acute organophosphate (OP) poisoning accounts for a large number of intoxication cases treated in the Intensive Care Unit (ICU). The aim of this study is to evaluate the performance of APACHE II, SAPS II, and SOFA scoring systems for predicting mortality of OP poisoned patients admitted to the ICU. Subjects and methods: Seventy three OP intoxicated patients admitted to the ICU of the PCC-ASUH during the period from June 2013 to June 2015 were prospectively evaluated through a cross sectional hospital based study.  Results: An APACHE II score of 10.5 or more was predictive of mortality, with 53.57 % sensitivity and 97.78% specificity. A SAPS II score of 25 or more was predictive of mortality, with 75.00 % sensitivity and 84.44% specificity. A SOFA score of 2.5 or more was predictive of mortality, with 75.00 % sensitivity and 91.11 % specificity. Conclusion:The three scoring systems, APACHE II, SAPS II, and SOFA, were more precise in differentiating the survivors from the non survivors than plasma butyrylcholinesterase.