Background: organophosphate (OP) poisoning is a major health problem worldwide, especially in developing countries, with millions of cases and hundreds thousands of deaths occurring each year.
The aim of this study: was to evaluate the role of Glasgow Coma Sale (GCS), serum cholinesterase (SChE) and S100B protein levels in evaluation and prediction of outcome of patients with acute organophosphate poisoning. 
Material and methods: the present study was conducted on admitted patients with acute organophosphate poisoning in Tanta Toxicological Unit, Tanta University Hospital during the period from the start of July 2014 to the end of June 2015.  For all patients; personal and toxicological history, complete clinical examination and measurement of SChE and S100B at admission and after 24hrs were performed for every patient. Outcome assessment; the patients were divided into two groups; group (1) included patients who survived and group (2) included patients who died.
Results: the present study was carried out on 24 patients with acute severe organophosphate toxicity, their age ranged from 16-48 years. Sixteen patients (66.67%) were survived and eight (33.3%) were died. About two third of the patients were female (66.67%), half of them were students (50%) and took malathion (50%). All patients took organophosphates orally and in a suicidal attempt. The GCS was higher in survived patients (6-11) than died ones (3-5). Additionally, serum S100B level at both admission and after 24hrs, revealed significant increase in its level in died patients than survived. While, SChE showed non-significant decrease in both survived and died patients. SChE and S100B at both admission and after 24hrs cannot predict mortality. However, GCS can predict mortality with 100% sensitivity and 75% specificity at a cut off level of 9. 
Conclusion: both GCS and S100B had significant correlation with the patients' outcome. Inspite of that, only GCS can predict mortality in 100% of the patients who has a GCS equal to or lower than 9. Also, 75% of survivors had GCS above this cut off value.