Microvascular anastomosis can be achieved by eversion of the upstream vessel end over an external cuff and insertion of this into the downstream vessel. This technique, first described in 1900, was initially tested in 13 rat femoral vein anastomoses using small polythene cuffs. Two anastomoses failed and 11 were patent at 7 days. After control studies, in 16 rat epigastric flaps the femoral vein in the vascular pedicle was divided and anastomosed using an external cuff. Thirteen flaps survived. The principles underlying this method appear sound, and form the basis for microvascular anastomotic devices currently being developed.