Aluminum phosphide (AlP) poisoning is a life-threatening emergency prevalent in the Middle East region including Egypt. Early prediction of prognosis is critical for initiating the utmost intensive interventions. Though many scoring systems were studied for predicting the prognosis of AlP poisoning, these scores received wide criticism. Complexity and reliability were the main concerns. Therefore, this retrospective cross-sectional study aimed to evaluate the performance of the recently introduced PGI score as a predictor of case fatality, the need for mechanical ventilation and vasopressor therapy in acute AlP poisoning. Moreover, it compares the performance of PGI with the known poison severity score (PSS), and the simplified acute physiology score (SAPS) II. Among 144 exposed patients, we reported a mortality rate of 61.1%. Non-survivors exhibited significantly higher PGI, PSS, and SAPS II than survivors. Though the PGI, PSS, and SAPS II proved their significance as predictors of mortality and, the need for MV and vasopressors, the PGI score showed a significantly higher area under the curve (AUC) as a predictor of MV (AUC = 0.848) compared to PSS (AUC = 0.731) and SAPS II (AUC = 0.749). Additively, PGI of 2 or more was a significant predictor of mortality (AUC = 0.831, sensitivity = 65.9%, and specificity = 89.3 %) and MV (p < 0.001), while PGI of 1 or more was another predictor of vasopressor need (AUC = 0.881, sensitivity = 89.0% and specificity = 79.4%). Given the PGI score's high AUCs across all outcomes, coupled with its balanced sensitivity and specificity, the PGI score could be a simple, and robust tool replacing the PSS and SAPS II for predicting mortality, clinical decision-making including the need for MV and vasopressor therapy in acute AlP exposure. Adopting the PGI score seems substantially useful in managing acute AlP poisoning, notably in resource-restricted countries.