A monoclonal antibody has previously been described that binds to all neurons in the 15 d (50% development) cockroach embryo but to only a small subset of neurons in the adult (Denburg et al., 1989). Experiments were performed in order to determine whether the developmental stage-specific antigen recognized by this antibody would reappear in adult neurons that were induced to undergo axonal regeneration by axotomy. It is demonstrated here that after nerve crush motor, sensory and interneurons undergo axonal regeneration and regain their ability to bind this antibody. This indicates that the developing and regenerating states of these neurons selectively use the same molecules to perform apparently similar cellular functions. The increase and subsequent decrease of antibody binding as a function of time after nerve crush was determined for each of these adult neurons. Correlations between the temporal distribution of the antigen and cellular events occurring during axonal regeneration are consistent with a role for this molecule in axon growth and the elimination of inappropriate synaptic connections. The antigen was localized to the external surface of the plasma membrane, and preliminary biochemical characterization has led to the tentative identification of the antigen as a glycolipid. These characteristics distinguish this growth-associated antigen from other previously described molecules whose temporal distribution has implicated a role for them in axon growth.