A newly recognized enterovirus, Giles virus, is held responsible for 58 cases of aseptic meningitis, three of them with paralysis. The new agent is distinguished by its affinity for human amnion cells in tissue culture. The virus was isolated from 45 cases; in 15 of these a rise in antibody titer was demonstrated. Clinically, the cases were typical. Giles virus appears to be more neurotropic than Coxsackie or ECHO viruses. There is evidence to suggest that experience with this virus is new in Minnesota.