From the combined procedures of skin stereomicroscopy of in situ grafts in rats, graft removal and supravital intracardiac injection of a contrast medium, the data suggest that the revascularisation of skin grafts is an orderly sequence of events which include: active invasion of the graft dermis by the ingrowing host capillary sprouts; development of anastomoses between the graft and host vasculatures; entry of blood into the graft through the vascular anastomoses by 48 hours after transplantation.