Background: Aluminum phosphide (ALP) is a highly lethal toxin with mortality rate 70-100%. Death frequently occurs in the first 12 to 24 hours due to cardiac and pulmonary toxicity, lactic acidosis, and adrenal insufficiency altering cortisol level and unfortunately there is no antidote found up till now. There is little data on biomarkers to predict outcome in ALP toxicity and we depend mainly on symptoms which are sometimes misleading. Aim: Assess the usefulness of measuring separately blood cortisol and lactate levels as predictors for early predicting the outcome in Aluminum phosphide intoxicated patients. Patients and methods: A prospective observational study was conducted from first of June 2022 till end of March 2023 on 40 patients of both sexes with acute ALP poisoning admitted to the Poison Control Centre, Ain Shams University Hospitals (PCC-ASUH) with maximum delay time 48 hours. Sociodemographic, intoxication and clinical data were collected for every patient. Investigations included Arterial Blood Gas Analysis (ABG) including lactate, and routine lab investigations in addition to blood cortisol, also electrocardiogram (ECG) were done. Outcome was also recorded. Results: Blood cortisol and the blood lactate levels were significantly high among deaths, pH, HCo3, So2 were significantly reduced in deaths compared with survivors. Conclusion: Biochemical abnormality of hyperlactemia and elevation of blood cortisol level can be used as predictors of mortality in ALP intoxicated patients, also hypoxemia and metabolic acidosis may point to possibility of mortality.