Despite frequent colonization of the newborn infant with genital mycoplasmas, morbidity due to these organisms has been cited on few occasions. This report describes an infant with suppurative submandibular lymphadenitis from whom Mycoplasma hominis was isolated in pure culture. CASE REPORT A 2,580-gm, firstborn, black, female twin was the product of a 36-week pregnancy in a 15-year-old primigravida in whom mild preeclampsia and fever developed one day prior to delivery. After spontaneous rupture of the membranes and a 12-hour labor, the infant was delivered without complication by low forceps and vacuum extraction. Apgar scores were 7 and 9 at one and five minutes, respectively; findings on routine newborn examination were unremarkable.