A study was conducted to compare the regeneration of rat peroneal nerves across 0.5-cm gaps repaired with artificial nerve grafts versus sutured autografts. The artificial nerve graft model is composed of a synthetic biodegradable passive conduit made of polyglycolic acid filled with a collagen extracellular matrix (predominantly Type I collagen, derived from calf skin, and with the telopeptide ends left intact). Axonal regeneration was studied in 22 long-term animals (11 or 12 months). The nerves were studied by qualitative and quantitative histological and electrophysiological methods, and by functional analysis in 9 of the animals. The axonal regeneration of the artificial nerve graft is equal to sutured autografts as measured by axonal counts, and by physiological and functional methods, although the sutured autografts demonstrated statistically superior axonal diameters.