The association between HLA and pulmonary tuberculosis was investigated in 50 Chinese patients. The frequencies of the HLA-A11 and -B15 antigens were increased (P less than 0.025) in patient group. Relative risks (R.R.) were 2.13 and 2.39, respectively. In contrast, the frequency of the HLA-Cw3 antigen and the R.R. (0.29) were decreased (P less than 0.005) in the patient group. These results are different from those reported by other researchers for Caucasian and Chinese tuberculosis patients. Moreover, it was found that the frequency of the A11-B15 haplotype in all patients with cavitation was 3-4 times higher (P less than 0.01) than in control individuals. The R.R. was 3.57.