Twelve rabbits were used to study functional nerve regeneration through macropore, semipermeable, and nonpermeable collagen conduits. Each animal underwent a 10-mm bilateral resection of posterior tibial nerve. Lesions were repaired with a macropore collagen tube in one leg, and with a semipermeable or a nonpermeable collagen tube contralaterally. Functional nerve regeneration was evaluated at 6 and 12 weeks post-repair periods. Functional recovery was assessed by electrophysiologic analysis of nerve conduction velocity, amplitude of nerve action potential, amplitude and area of muscle action potential, and by quantitative and qualitative histologic analysis of myelinated nerve fibers from the distal nerve stumps. The macropore-collagen-tube group showed significantly greater functional recoveries than semipermeable or nonpermeable collagen-tube groups, based on electrophysiologic and histologic analyses.