The incidence of infections of the central nervous system caused by Mycoplasma hominis in newborn infants is not known. However, such infections occur in both full-term and premature infants, either with or without malformations such as myelomeningocele. M. hominis has also been recovered from brain abscesses. Infected infants usually present with signs of meningitis or meningoencephalitis. Hydrocephalus may develop. The cerebrospinal fluid characteristically has a reduced glucose content and an elevated protein concentration. The white blood cell count is high, with a predominance of either mono- or polymorphonuclear leukocytes. Cerebrospinal fluid yields M. hominis but not other bacteria. Some newborn infants with M. hominis infection of the central nervous system die, whereas others survive and become healthy. In spite of adequate antibiotic therapy, some of those infected develop sequelae such as hemiplegia. Therapy with tetracycline or lincomycin can rapidly eradicate the organism from cerebrospinal fluid.