Poisoning with Organophosphate (OP) compounds is responsible for great morbidities and mortalities all over the world especially in developing countries including Egypt. Scoring systems have been continuously developed to predict outcomes in patients with severe illness, to improve resource allocation and to assist in clinical decision-making particularly for ICU patients. The quest for biomarkers in relation to OP compound poisoning started quite a long time back but cheap and easily measurable biomarkers having prognostic value is the need of the hour. The objective of this study is to evaluate the role of acute physiology and chronic health evaluation II (APACHE II) score, the Sequential Organ Failure Assessment (SOFA) score, serum amylase and lipase in assessing severity and outcome of acute organophosphorus poisoning.A retrospective and prospective study was carried out on 200 patients of acute OP poisoning admitted to the Poison Control Center (PCC), Ain Shams University Hospitals. Information  after obtaining the permission of the director of PCC and the regional ethics committee was collected from the sheets and computerized data base of the patients, an informed written consent has been obtained from each patient or from his/her caregiver for inclusion in the prospective part of the study. APACHE II and SOFA scores were calculated to each patient admitted and biochemical analysis of serum amylase and lipase were estimated in the prospective part of the study. The results were revised, coded and organized for statistical analysis. The study results revealed 180 (90%) patients discharged and 20 (10%) patients died. The study showed that there were 76% of patients had APACHE II score ≤ 9, while 12.5% of patients had APACHE II score from 10 to 14, there were 8.5% of patients had APACHE II score from 15 to 24 and APACHE II score was > 24 in 3% of patients. SOFA score in 88.5%of patients was ≤ 6, while in 4.5% of patients SOFA score was from 7 to 9 and in 7%of patients SOFA score was > 9. Hyperamylasemia observed in 83.3% of died and 33.3% of died patients had increased lipase. There was significant difference between discharged and died patients as regards APACHE II score, SOFA Score, serum amylase and lipase. It could be concluded that SOFA score, APACHEII score, serum amylase and lipase had a role in assessment of severity of acute organophosphorus poisoning but only SOFA score, APACHEII score and serum amylase could be used as predictors of outcome. SOFA score is more useful in predicting mortality, and easier and simpler than the APACHEII and serum amylase. From the previous results, our study recommends that predictors of outcome (APACHE II score, SOFA score and serum amylase) should be assessed routinely and as early as possible to evaluate the severity, improve the course of management and deciding the pathway of care.