Neuromas can be painful and physically and psychologically disabling. Among the many methods of treatment available, translocation away from noxious stimuli, such as implantation in muscle or bone, has been used. Veins are easily available and accessible to nerves. The outcome of a nerve ending implanted into a vein and the effects of the implanted nerve on the vein have not been studied. This study evaluated neuroma prevention with a new technique that involves implanting a nerve ending into a vein. The medial branches of the right femoral nerve of 20 rats were transected at midthigh level. The distal segments were excised. The proximal segments were implanted into the femoral vein. The epineurium was sutured to the tunica adventitia using interrupted 10-0 Ethilon sutures. The left side served as controls where the proximal nerve stumps were left lying in their beds. The animals were sacrificed 12 weeks after the operation. Histologic analysis of 12 controls showed neuromas. Twelve implanted nerves showed neuromas that were smaller than those of the controls. The difference was statistically significant. The regenerated nerve fibers were found within the adventitia and muscular wall of the vein. There was no extension of nerve tissue into the vessel lumen and no thrombosis of the vein. Electron microscopic study on the other eight rats showed abnormal large myelinated fibers in the controls and in the implanted nerves. The fibers in the implanted group were degenerated.