Graft-versus-host disease (GvHD) includes inflammatory and/or fibrosing manifestations that may arise at various times after transplantation of any organ containing lymphoid cells. For the dermatologist, the importance of GvHD is real and current. Indeed, because it has become easier to perform bone marrow transplantation (EMT), the indications of BMT have become broader, making follow-up of patients receiving grafts a widespread practice. Nonetheless, GvHD remains a frequent complication of BMT and its principal target organ is the skin. Furthermore, recent innovations, such as grafting of umbilical cord blood and the mobilization of peripheral blood progenitor cells, will be the source of new questions concerning the development of GvHD under these conditions. Finally, because of its analogies with other spontaneous idiopathic skin diseases, GvHD constitutes a model that may lead to a better understanding of the pathophysiological features of these diseases. In this review, the cutaneous aspects of GvHD are emphasized.