Introduction: Aluminum phosphide (Alp) poisoning is a major health problem developing countries because of the high rates of morbidity and mortality even in well-equipped and experienced hospitals.. The aim of this study: Was to evaluate various scoring system (Acute Physiology and Chronic Health Evaluation (APACHE) score, Rapid Emergency Medicine Score (REMS), The Sequential Organ Failure Assessment (SOFA) score) at admission for outcome prediction in acute aluminum phosphide poisoned patients. Patients and methods: The present study is a cohort study that was carried out on acute Alp poisoned patients at Poison Control Unit, Tanta University Emergency Hospital. It was composed of two periods; one year retrospective (from April 2015 to March 2016) and six months prospective (from April 2016 to September 2016).All admitted patients over 16 years with acute aluminum phosphide poisoning were included in this study. Patients were grouped according to their outcome into survivors and non survivors. From the collected data, APACHE II, SOFA and REMS scores were calculated for every patient. Results: The present study was carried out on admitted fifty acute Alp poisoned patients. Out of them, survivors represented 44% and 56% were non-survivors. The majority of patients were in the age group 16-20 years, females, student, from rural areas (90%) and most of patients had ingested phosphides intentionally in a median dosage of one tablet. Hypotension, tachypnea, metabolic acidosis, hyperglycemia and higher serum creatinine levels and alanine transaminase (ALT) at admission, were risk factors of mortality from Alp. Non survivors had significantly higher APACHE II, SOFA and REMS score values than survivors. SOFA score had the best AUC (0.989) followed by APACHE II score then REMS score (0.987 and 0.970 respectively). However, no significant differences between AUC values of compared scores could be demonstrated. Conclusion: The clinical scores (APACHE II, SOFA and REMS) were similar and effective tools for determination of the severity of acute Alp poisoning. However, REMS proved to be more applicable than other scores owing to its simplicity, less time-consuming and effectiveness in emergency situations. Therefore, REMS score is suggested to be used in the emergency situations to predict outcome in Alp poisoned patients.