The aim of this study was to show the evolution of diagnostic techniques revealing an abnormal origin of the left coronary artery and present the follow-up results of patients operated for this malformation at different ages. This retrospective study includes 36 children or adults, with a mean age at the moment of of 28 months old, ranging from 7 days to 39 years. In 9% of cases, patients were asymptomatic. Before 1990, 81% of children had a cardiac catheterization, versus 25% after. Indeed, echocardiography with color Doppler enabled the diagnosis of abnormal origin of the left coronary artery in 70% of cases. The pre-operative mortality is at 21% (12.5% after 1990). Twenty-three patients had surgery: left coronary artery reimplantation (n=16), bypass (n=5), at mean of 44 months old for the entire series, but 21 months old after 1990. The follow-up was clinical, ECG and radiographic and echocardiographic after 1975; when possible an exercise test, cardiac nuclear imaging and more recently coronary CT scan and MRI have been performed. In conclusion, children are operated earlier and the follow-up should focus on the detection of occlusion of the re-implanted left coronary artery by echocardiography, with or without stress, exercise test, cardiac nuclear imaging, MRI and sometimes, coronary angiography.