We are developing functional autologous tubular tissues, called biotubes, as ideal small-caliber vascular grafts that have growth potential without immunological rejection. In this study, to improve surgical handling, a novel biotube reinforced at the anastomosis regions was designed. Silicone rods, 2 mm in diameter and used as a mold, were covered with two pieces of short polyurethane sponge tubing as anastomotic reinforcement cuffs at both ends. After the assembly was placed into dorsal subcutaneous pouches in rabbits for 1 month, seamless biotubes incorporating the cuffs were obtained. The interstices and surfaces of the cuffs were impregnated and covered with connective tissues similar to those of the biotubes, mainly consisting of collagen and fibroblasts. Since the tubular shape of both ends was rigidly maintained, end-to-end anastomosis by conventional microsurgery techniques between biotubes and native carotid arteries was very easy. In preliminary autoimplantation studies, angiographic observation of up to 2 months duration showed no formation of aneurysms or rupturing.