In HIV-1-infected patients, oral manifestations such as recurrent apthous ulcers are often seen. A total of 29 HIV-infected patients were examined to determine salivary tumour necrosis factor alpha (TNFalpha) concentrations by enzyme-linked immunosorbent assay, the amount of HIV-1 RNA copy by Amplicor HIV-1 Monitor test, number of CD4 cells by flow cytometry and oral manifestations by oral examination. TNFalpha concentration was significantly correlated with the amount of HIV-1 RNA, however, not with the number of CD4 cells in HIV-1-infected patients. Further, patients with oral manifestations showed significantly higher concentrations of TNFalpha in saliva and HIV-1 RNA copies in serum than those without oral manifestations. Following recovery from oral ulcers, TNFalpha concentration was decreased by half to 20 times lower than the level of that during ulcer incidence. Our results suggest that salivary TNFalpha is a good indicator for oral manifestations and HIV RNA amounts in HIV-1-infected patients.