Baylisascaris procyonis,the common raccoon roundworm, is a rare cause of devastating or fatal neural larva migrans in infants and young children. We describe the clinical features of two children from suburban Chicago who developed severe, nonfatalB. procyonisneural larva migrans. Despite treatment with albendazole and high dose corticosteroids, both patients are neurologically devastated. In many regions of North America, large populations of raccoons with high rates of endemicB. procyonisinfection live in proximity to humans, which suggests that the risk of human infection is probably substantial. In the absence of effective treatment, prevention of infection remains the most important public health strategy.