Baylisascaris procyonis is an ascarid which parasitizes the small intestine of raccoons. The parasite is not very pathogenic in the raccoon because larvae do not migrate in this host. In other animals the larvae migrate through the body. They do not develop into adult worms in the intestine but rather become encysted in granulomas, showing a preference for the brain. In humans these larvae cause different larva migrans syndromes. Patients with neural larva migrans syndrome show severe brain symptoms and the disease is sometimes fatal. This article describes the life cycle of the worm and the incidence, symptoms, diagnosis, treatment, and prevention of larva migrans syndromes, paying special attention to the Dutch situation.