This projects studies the concept of vulnerability in the specific field of biomedical research. It analyses and compares the definition of vulnerable persons and their type of vulnerability in European law both from the European Union and from the Council of Europe, as well as in major ethical or professional international guidelines dealing with the topic. Two main observations can be made. First, protection of vulnerability is often too narrowly limited to legal incapacity whereas litterature shows that decisional vulnerability can concern anyone under financial, hierarchical or familial pressure etc. Second, vulnerability is most of the time limited to this decisional vulnerability, leading to paternalistic behaviours excluding many people from biomedical research. On the contrary, some peope may have a rather clinical vulnerability that would necessitate researchers to study their vulnerability and treat them properly. Therefore, this project suggests a concept of vulnerability in biomedical research that would allow a more personnalized and adequate protection of vulnerable persons depending on what they are vulnerable to.