The objective of this work is to give epidemiological data, established in a prospective way, on the myocardial infarction in young and its risk factors. All patients admitted to the CHG of Pau for myocardial infarction, old, for the men of less than 45 years and for the women of less than 55 years, of November the 1st 2002 to October 31st, 2003, are included. Twenty-seven patients (11.2%) do a myocardial infarction including 44.4% women. The found traditional risk factors are: smoking (92.6%), absence of regular physical activity (81.5%), dyslipidaemia (66.7%), family history of cardiovascular disease (48.2%), hypertension (37.0%), obesity (18.5%), oral contraception (11.1%), diabetes (7.4%), personal thrombotic history (7.4%). The principal emergent risk factors highlighted are: stress (66.7%), inhibitor of the activation of the plasminogene (57.1%), C-reactive protein (50%), lipoprotein a (41.7%), fibrinogen (33.3%), elevated plasma homocysteine (25%), excessive alcohol use (22.2%). None patients does not have an absolute cardiovascular risk > 20%. The clinical characteristics, coronarographic data and the acute treatments were also listed. The prognosis is worse for the women with more risk factors, more complications, and risk of more significant ventricular replanning. The principal risk factors of the myocardial infarction in young can be modifiable. The prevention is of primary importance. The therapeutic education of the patients corresponds to the total assumption of responsibility required by this pathology.