Introduction: Aluminum Phosphide “ALP" tablets are frequently used to commit suicide in developing countries and Egypt. Mortality is very high; it can induce oxidative stress and alter antioxidant defense system. Aim of the Work: This study aimed to evaluate malondialdehyde “MDA" and total antioxidant capacity “TAC" as oxidative stress biomarkers in acute ALP poisoning and correlated them with poisoned patients' outcome and mortality. Subjects and Methods: This study was conducted on 120 individuals of both sexes divided into; (Group I) included 60 acute ALP poisoning patients, presented within 6 hours of exposure to Toxicology Unit of Emergency Hospital, Mansoura University and the remaining 60 (Group II) were healthy individuals as control group. Results: Serum level of MDA was significantly increased, and TAC was significantly reduced in ALP poisoned group at time of presentation in comparison to control group. On the other hand, levels of MDA and TAC were statistically significant difference between survivors and expired groups. In addition, serum MDA and TAC were found to be sensitive in prediction of ALP mortality. However, MDA level showed maximum specificity as well as more accuracy for prediction of poor outcomes. Conclusions: It can be concluded that, ALP exerts its toxicity through developing disproportionate oxidative stress and compromising antioxidant protective mechanisms. Both MDA and TAC were sensitive in prediction of ALP mortality and serum MDA level could be used as a more sensitive specific predictor biomarker for poor prognosis in acute ALP poisoning.