BACKGROUND. Oral lesions are common findings in HIV-related disease, but little is known about their significance in predicting immune suppression among a representative group of HIV-infected persons. METHODS. Oral examinations were performed on 454 patients who came to an outpatient dental clinic for dental care. CD4+ cell counts were obtained within 2 months of the examination. RESULTS. In persons with a specific lesion and a CD4+ cell count below 200 cells/mm3 the corresponding mean CD4+ cell counts and predictive values were 149.5 cells/mm3 and 69.9% for candidiasis, 143.3 cells/mm3 and 70.1% for oral hairy leukoplakia, 126.0 cells/mm3 and 69.4% for xerostomia, 51.8 cells/mm3 and 95.1% for necrotizing ulcerative periodontitis, 98.7 cells/mm3 and 87.0% for long-standing herpes simplex virus infections, 66.6 cells/mm3 and 93.6% for Kaposi's sarcoma, and 33.7 cells/mm3 and 100% for major aphthous ulcers. The mean CD4+ cell count declined with increased numbers of different concurrent lesions. CONCLUSION. The presence of specific oral manifestations and the number of different concurrent intraoral lesions among HIV-infected persons are associated with severe immune suppression and AIDS. Oral examinations are an essential component for early recognition of disease progression and comprehensive evaluation of HIV-infected patients.