Stomatococcus mucilaginosus was isolated from eight neutropenic patients during nine febrile episodes over a 13-month period. Five of these isolates were from definite infections, including one case of fatal meningitis. This slime-producing, catalase-variable, gram-positive coccus is a component of the normal oral flora of humans. Its biochemical profile may result in misidentification; however, unlike most micrococci, it characteristically fails to grow on media containing 5% NaCl. All but one of our isolates were sensitive to benzylpenicillin, and all were sensitive to vancomycin. S. mucilaginosus may prove to be an important pathogen in severely immunocompromised patients.