Résumé : Surrogate motherhood is one of the methods for medically assisted procreation that is nowadays most controversial. Indeed, its legitimacy is open to debate due to the way it shakes up all conventional representations of the family and parenthood. Seeking to better understand this phenomenon, the study taken up in the present article investigated the motivation of surrogate mothers offering their services to a couple wishing to have a child and resorting to surrogacy. Four women were encountered and asked to tell about how they went through that experience. The methodology is qualitative and includes a semi-structured interview rounded off by two genograms. The main results concerning the surrogate mothers' motivations are reported. Two aspects in particular retained our attention: their high level of empathy and the presence of a sense of indebtedness providing the mainspring for their action.