We have used a monoclonal antibody (5F4) and Griffonia lectin to study the recruitment of macrophages after crushing axolotl central and peripheral axons. In both cases axonal regeneration begins within one to two days and, in the CNS, proceeds at a rate of about 0.05 mm per day. However, in the spinal cord, macrophage entry is restricted to the lesion site whilst in peripheral nerves macrophages rapidly enter the distal nerve stump after injury. These results suggest that the role (if any) played by macrophages during axonal regeneration may differ in these two situations.