The medical certificate of no contraindication to the practice of sport, requires prudence during the exam preceding its writing for medicals and medico-legal reasons. It needs a careful questioning on important points relative to the risk of health problems during a sportive effort, especially to seek for the prodoms which can be found in 7 to 50% of cases. This questioning can sometimes be specific to certain specialities of sport. Actually, even if the concept of mass screening identify for sports people, amateurs or not, is still much debated, we can consider as a reasonable attitude, in consulting with the general medicine, to practice a careful cardiovascular examination and an ECG whose the interpretation, done with the expertise required, could help to detect about 60% of the possible lethal abnormalities to the physical effort. In case of doubt during the exam, the complementary investigations are needed in some cases (echocardiogram, stress testing, myocardial perfusion, electrophysiological endocavitary exploration). After that, the used advices can be given to the sportive candidate to minimize the risks. Despite these precautions, a subit death because of the effort can non totally be avoided. Finally, it must be remembered that the behaviour to have for kid and for elderly person involves certain specificities to know.