The proper selection of a recipient vessel is essential for the success of free tissue transfer, especially when the transfer is to the lower extremity. However, a general agreement on which vessel to use has not been reached yet. Conflicting data have been reported on the survival and outcome of the transferred flaps, depending on the vessel used or the location of anastomosis. The aim of this study was to identify the patterns and problems in the selection of recipient vessels for free tissue transfer to the lower extremity and to establish a general guideline for proper selection. From September of 1990 to December of 1997, 50 consecutive, microvascular, free tissue transfers were performed on the lower extremity. The causes requiring soft-tissue coverage included trauma (25), unstable scar (11), chronic osteomyelitis (7), and tumors (7). The mean follow-up period was 22.4 months (range, 2 to 41 months). In 25 cases, the posterior tibial vessel was used as the recipient vessel. The microvascular anastomosis was done proximal to the zone of injury in 45 cases. The two most important factors in the selection of a recipient vessel are the site of injury and the vascular status of the lower extremity. Less important factors include the flap to be used, method, and site of microvascular anastomosis. All the currently feasible options for recipient vessels are included, and the opinions of other surgeons are reviewed. A general guideline is established, and an algorithm for the proper selection of a recipient vessel is proposed. This algorithm is a fast and convenient guide for evaluating the wound and planning the free flap to the lower extremity.