This is apparently the second report of a case of human meningoencephalitis caused by the nematode Micronema deletrix. The patient had severe granulomatous meningoencephalitis with numerous foci of hemorrhage and encephalomalacia. Numerous adult female and larval M. deletrix were in the brain. The organisms probably inhabit decaying organic material, but occasionally parasitize the kidney, nose, or central nervous system of the horse. In its parasitic form the nematode replicates parthenogenetically.