Acute myocardial infarction (AMI) is rarely associated with antiphospholipid syndrome. The treatment of these patients is a clinical challenge. We report the observations of 2 young adults (1 woman and 1 man), admitted in our acute care unit for acute myocardial infarction (AMI). A coagulopathy work-up concludes the existence of antiphospholipid syndrome (APS) in the 2 cases. APS syndrome was considered primary in 2 cases. All patients presented an intense inflammatory syndrome (high level of CRP). Anticardiolipine was present in the 2 cases. However, anti B2 glycoprotein I antibodies were detected in only one case. Emergency percutaneous transluminal coronary angioplasty (PTCA) with direct stenting had been performed successfully only in the first case, and the follow-up was uncomplicated. Thereafter, long-term oral anticoagulant appeared to be effective. The last patient was admitted because of peripheral acute ischemia of legs. Standard electrocardiogram showed signs of previous silent anteroseptal wall myocardial infarction confirmed by echocardiography. The latter revealed an apical thrombus and a very low left ventricular ejection fraction. Amputation of the right leg was necessary because of consultation occurred too late. However, he died four weeks later. Primary antiphospholipid syndrome should be considered as a cause of acute myocardial infarction in young adults, and PTCA with anticoagulant treatment is effective for initial treatment of this complication.