A case report of an AIDS patient afflicted with disseminated histoplasmosis is presented. Characteristic granulomatous-appearing lesions on the tongue were observed during the patient's initial workup, but the patient became unavailable for a scheduled biopsy. Consequently, the diagnosis of a histoplasmosis infection was established only after the performance of several time-consuming, stressful, and, at times, invasive diagnostic procedures. It is proposed that early histologic evaluation of the suspicious oral lesions would have resulted in the diagnosis, thus making more extensive diagnostic testing unnecessary. This case illustrates the need for the dentist to pursue an aggressive approach in evaluating oral lesions in the AIDS patient.