Abstract Several European law documents (including the Charter of Fundamental Rights of the European Union) lay down a general prohibition on making the human body and its parts, as such, a source of financial gain. Scholars have identified three reasons for this prohibition: human dignity, equality, and solidarity. This paper aims at exploring to what extent non-gratuitous contracts on human biological samples can be validly concluded for purposes of research and commercial applications of the research results. In particular, the present paper will firstly, analyse the role of the three aforementioned reasons – dignity, equality, and solidarity – in the assessment of the validity of non-gratuitous contracts on human biological samples for the purposes of research and possible commercial uses thereof. Secondly, this paper will outline some possible advantages of excluding this kind of contracts from the scope of application of the prohibition of financial gain.