The present study is a determination of the numbers of axons in the sural nerve and nerve to the medial gastrocnemius muscle following section and regeneration of the sciatic nerve in the rat. The data indicate that there is a significant increase in both myelinated and unmyelinated axons in the nerve to the medial gastrocnemius muscle and a significant increase in myelinated but a significant decrease in unmyelinated axons in the sural nerve. Thus axonal numbers do not return to normal and the axonal responses are different in different tributary nerves when the parent nerve is cut and then regenerates.