Peptococcus saccharolyticus was a numerically important organism on the forehead and the antecubital fossa of the arm of ca. 20% of the subjects studied. It was best detected by prolonged (4- to 7-day) anaerobic incubation on a suitably enriched medium but also appeared in smaller numbers in aerobic primary cultures after 4 to 7 days. Initial screening was based on growth patterns in shake cultures and on the relative amounts of growth on aerobic and anaerobic streak plates. The organism was nonhemolytic and usually catalase positive. It produced acid anaerobically from glucose, fructose, and glycerol, but not from maltose, and did not produce lactic acid from glucose.