This report is the first to describe coronary vasospasm, diagnosed by cardiac magnetic resonance imaging in an adolescent, resulting from marijuana abuse. A previously healthy 17-year-old male patient with severe chest pain, electrocardiographic changes, and urine test positive for cannabis, was diagnosed of having transient myocardial ischemia. The patient was discharged home and at this writing remains asymptomatic with a follow-up echocardiogram after 1 month showing normal left ventricular systolic function. Marijuana should be considered in the etiology of transient coronary vasospasm leading to myocardial ischemia in otherwise healthy adolescents. Cardiac magnetic resonance imaging is a safe and effective method for diagnosing coronary vasospasm.