Axonal injury induces cell death in selectively vulnerable motor neurons of immature animals. This extensively studied animal model of trauma-induced motor neuron death is being used to develop the theoretical basis for the therapeutic use of neurotrophic factors to “rescue” dying neurons in amyotrophic lateral sclerosis, Parkinson's disease, and Alzheimer's disease. Antecedent trauma has been implicated as a precipitating factor for amyotrophic lateral sclerosis in susceptible individuals. The animal model of traumainduced motor neuron death provides support for the concept that motor neurons in individuals susceptible to amyotrophic lateral sclerosis may be selectively vulnerable to trauma producing axonal injury. The case histories of six young adult men who developed amyotrophic lateral sclerosis after trauma with axonal injury are presented.