Sleeve anastomosis is an end-to-end variant (i.e., end in end) that makes it possible to suture two vessels quickly and with few stitches. Various methods have been described in the literature concerning experimental surgery (microsurgery and transplantation) and clinical microsurgery. The authors tested for a method that would eliminate narrowing of the inserted vessel segment and that would improve efficiency and feasibility of the technique. The experimental study was performed in 60 rats weighing 200 to 400 g. Telescoping microanastomosis consists of hemi-invagination of a 2-mm-caliber artery at high pressure (subrenal aorta), sidecut of the distal wall of the external arterial segment, and suture with three endoluminal stitches. A total of 61 anastomoses were subdivided in three groups: (1) one-sleeve anastomosis, (2) double-sleeve anastomosis with interposition of an arterial graft, and (3) a control series of conventional end-to-end anastomoses. Patency rates of 95% to 100% at 1 week and 1 month demonstrated no differences among groups.