We describe a case of primary aspergillosis involving the tongue of a patient with acute myeloid leukemia. Intraoral aspergillosis is very rare and we found only 23 cases reported in the English literature. Clinically it was a 2-cm, ulcerated, grayish lesion on the dorsum of the tongue. Microscopically there was invasion of the epithelium, connective tissue and muscle of the tongue by fungal hyphae branching at 45° angle. The large hyphae were easily seen by H & E stain, and were strongly positive for periodic acid-Schiff and Grocott methenamine. The patient was successfully treated with intravenous amphotericin B. Based on clinical, microscopic and culture data, the diagnosis of primary aspergillosis of the tongue was established. Invasive oral aspergillosis is a potentially lethal disease and it should be considered in immunosuppressed patients.