Acute pyogenic meningitis occurred in a 46-year-old woman receiving long-term steroid therapy. Cultures for bacteria and fungi were negative, and the meningitis failed to respond to broad spectrum antibiotics. Abundant Strongyloides stercoralis larvae were found in the patient's feces a sputum, and a filariform larva was found in a hanging drop preparation from centrifuged cerebrospinal fluid. Therapy with thiabendazole eradicated the Strongyloides from feces and sputum. The abnormal CSF values returned toward normal, and the patient has had no recurrence of illness.