Meningitis is an unusual manifestation of infection caused by Blastomyces dermatitidis. We describe a patient who presented with fulminant blastomycotic meningitis. Examination of the lumbar CSF demonstrated > 5,000 polymorphonuclear leukocytes/mm3. The diagnosis of B. dermatitidis meningitis was initially suggested by cytologic examination of CSF and confirmed by culture. Pleocytosis of this magnitude had not been previously described in association with blastomycosis, although review of the published literature revealed that neutrophilic pleocytosis is a common manifestation of blastomycotic meningitis and should suggest the diagnosis. This report broadens the clinical spectrum of blastomycotic meningitis and suggests that cytologic examination of CSF is a useful way to establish this diagnosis.