BACKGROUND Organophosphates are potent cholinesterase inhibitors that when ingested in excessive amounts can be fatal. Organophosphorus poisoning has become an important clinical problem with increased mortality in the country from accidental or intentional ingestion of, or exposure to the pesticide. This study aimed to find out the prevalence of organophosphorus poisoning among patients admitted to the Intensive Care Unit of the Department of Internal Medicine in a tertiary care centre. METHODS A descriptive cross-sectional study was conducted among patients admitted to the Intensive Care Unit of the Department of Internal Medicine of a tertiary care centre after receiving ethical approval from the Institutional Review Committee (Reference number: 2003202205). The study was conducted between 1 February 2021 and 1 February 2022 using hospital records. Convenience sampling was done among the patients who met the eligibility criteria. The diagnosis of organophosphorus poisoning was made based on the patient's history, clinical examination and the measurement of serum acetylcholinesterase levels. Point estimate and 95% Confidence Interval were calculated. RESULTS Among 1108 patients admitted, organophosphorus poisoning was seen in 50 (4.15%) (3.29-5.73, 95% Confidence Interval). CONCLUSIONS Our study found that the prevalence of organophosphorus poisoning was lower when compared to similar studies done in similar settings.