Background and Aims: Organophosphorus (OP) compound poisoning is one of the most common poisonings in India. The aim of the study was to study the outcomes and predictors of mortality in patients with acute OP poisoning requiring mechanical ventilation. Methods: A retrospective study was conducted in the intensive care unit and 117 patients were included. Diagnosis was performed from the history taken either from the patient or from the patient′s relatives. Demographic data, month of the year, mode of poisoning, common age group, duration of mechanical ventilation, time of starting pralidoxime (PAM), and mortality were recorded. Chi square test, Pearson correlation test, and multivariate binary logistic regression analysis was used. Data are presented as mean ± SD. Results: 91.86% (79/86) of cases were suicidal and remaining cases were accidental. Duration of mechanical ventilation varied from less than 48 hours to more than 7 days. Mortality rate was 33.3%, 7.2%, and 100% in those who required mechanical ventilation for more than 7 days, 5 to 7 days, and 2 to 4 days, respectively. Lag time was less than 6 hrs in 13 patients and all of them survived. 17.1% and 28.1% patients died in whom PAM was started 6 to 12 hrs and 13 to 24 hrs after poisoning, respectively. There was statistically significant positive correlation between lag time of starting of PAM with duration of mechanical ventilation and total dose of PAM (P < 0.0001). None of the predictors age, lag time, severity of poisoning, and duration of ventilation were independent predictors of death. Overall mortality rate was 18.6%. Conclusion: Mortality from OP compound poisoning is directly proportionate to the severity of poisoning, delay in starting PAM, and duration of mechanical ventilation. Death is not dependent on a single factor, rather contributory to these factors working simultaneously.