Objective: Toreport a causal relationship between myocardial infarction (MI) and obesity in an adolescent in the absence of the well-known risk factors for MI. Case Presentation and Intervention: A morbidly obese 17-year-old male, a nonsmoker, nondiabetic and normotensive patient, who sustained acute inferior MI with no family history of coronary artery disease, presented with central chest pain. ECG showed low voltage, normal sinus rhythm and ST segment elevation in the inferior leads; cardiac enzymes were elevated. Screening for ethanol and cocaine were negative. He was admitted to the coronary-care unit as a case of inferior MI with late presentation. Cardiac catheterization revealed patent epicardial coronary arteries; short- and long-term plans for weight reduction and family counseling were started. The hospital stay was uneventful, and the patient was discharged home on the fourth day. Conclusion: Based on clinical and laboratory findings, we assume that the MI might partly be secondary to coronary artery spasm or invisible premature atherosclerotic plaques. Public education and awareness for this complication in a young obese patient are warranted.