A 32-yr-old white North American male resident of Norway presented with an asymptomatic radiolucency first identified 3 yr after the removal of an impacted mandibular right third molar in Southern California 16 yr previously. Surgical exploration revealed an intraosseous cavity filled with a black, homogeneous, gelatinous substance thought to be foreign material, but which was diagnosed histologically as containing black yeasts. Cultivation of a microbiologic sample for 6 wk grew black yeast-like colonies. The yeast isolate was identified as an Aureobasidium species different from the typical A. pullulans. A blood sample was negative with regard to antibodies both with double diffusion technique and ELISA. Also, examination with respect to dermatologic manifestations gave negative results. Flucytocin 10 g/d was administered systemically for 30 d. Six months postoperatively bone regeneration was satisfactory radiologically.