Background Organophosphate poisoning is the commonest accidental and suicidal poisoning in developing countries like Nigeria. Respiratory distress, unconsciousness, and acute cholinergic crisis are reasons for critical care. Objective We determined the clinical presentation and outcome following sniper poisoning in critically ill patients. Methods This was a retrospective case series of 13 patients managed for sniper poisoning in a six-bed private intensive care unit in Lagos, Nigeria, from June 2016 to June 2022. The diagnosis of sniper poisoning was made based on a positive history of ingestion of sniper before presentation, and clinical signs of cholinergic hyperactivity. Results A total of 13 patients were reviewed, 3 females and 10 males with median age and APACHE II score of 23.5 years (IQR, 5.75, 27.75) and 26 (IQR, 24, 27.5), respectively. Deliberate ingestion of sniper occurred in 10 patients. Respiratory insufficiency/unconsciousness, and bradycardia/hypoxia occurred in 11 and 10 patients, respectively. The median duration of ICU admission was 6.5 days, (IQR: 4, 8). Intravenous atropine and glycopyrrolate were administered in 10 and 2 patients, respectively. The median dose of atropine on days 1, 2, and 3 were 38.9 mg, 27.6 mg and 18.5 mg, respectively. Mechanical ventilation was initiated in 10 patients, 8 of whom were discharged home. Out of 13 patients, 10 survived, while 3 died. Conclusion This case series showed that sniper poisoning is a life-threatening condition that requires immediate diagnosis and treatment. Early referral for critical care, initiation of atropine, and supportive mechanical ventilation can save lives.