BACKGROUND Acute myocardial infarction is rare in people under the age of 30. OBJECTIVE To determine the clinical features and outcome in young patients presenting with AMI. METHODS All patients aged 30 years and younger hospitalized with AMI during a period of 8 years (1993-2000) were evaluated for clinical features and outcome. RESULTS Of the 3,758 patients with AMI, 15 were 30 years old or younger (0.4%). The mean age was 28 (range 21-30 years) and all were male. Eight had normal coronary arteries on angiogram; seven had obstructive coronary artery disease. Patients with OCA had more classical risk factors for coronary disease. A complete diagnostic workup was abnormal in four patients with NCA: thrombophilia in two patients, spasm due to alcohol withdrawal and hyperthyroidism in one patient each. All patients presented with typical new-onset chest pain. None had a previous history of angina. All patients with OCA received reperfusion therapy as compared to one patient with NCA. Peak creatine phosphokinase in NCA and OCA was 504 +/- 547 and 1,328 +/- 440 respectively (P < 0.01). All patients with NCA had good left ventricular function on follow-up echocardiography, compared to only three in the OCA group (P = 0.02). There was one death due to cardiogenic shock in a patient with OCA. Follow-up of 4 +/- 2 years demonstrated recurrent acute coronary syndromes in four of seven patients with OCA versus none in the NCA patients (P = 0.02). CONCLUSIONS AMI is rare in very young patients, and more than half NCA. A thrombophilic tendency or spasm should be considered. Young patients with NCA have an excellent prognosis.