An extensive examination of the tongue was performed at autopsy in 20 consecutive patients who had died with AIDS. Abnormalities in the tongue were detected in 18 (90%) of the cases; the commonest lesions were ulceration (11), candidosis (8) and small foci of hyperkeratosis (10). The most extensive lesions were caused by Aspergillus infection (1), non-Hodgkin's lymphoma juxtaposed with Kaposi's sarcoma (1), herpetic infection (1) and candidosis (5). The disease causing death was identified in the tongue in two cases. There was a surprisingly low prevalence of oral hairy leukoplakia, which may be related to anti-viral or retroviral therapy.