The prevalence of mycobacterial infection in AIDS patients has increased in Japan. This report describes details of the clinical and radiological features of eight AIDS patients with mycobacterial disease (6 with M. tuberculosis infection and 2 with M. kansasii infection) in our hospital during the period from October 1995 through February 1997. Six of the 8 were men, and two were women. The mean age was 36.5 years. Six were Japanese, one was from Myanmar, and one was Malaysian. The median CD4 positive T lymphocyte counts (CD4 count) at the time of diagnosis of the M. tuberculosis was 75.5 (range 14-569/microliter, and the M. kansasii was 21.5 (range 19-24)/microliter. Clinical findings and symptoms of all patients were non-specific, but almost all patients had a cough and fever. In the radiographic findings, the patients of the M. tuberculosis group presented multiple hilar and mediastinal lymphadenopathy, miliary shadow, and obstructive pneumonia. Both M. kansasii patients showed a multiple infiltration shadow. There were no drug resistant strains in M. tuberculosis except on isolate with moderate resistant. to Streptomycin. These observations suggest that AIDS-associated mycobacterial disease shows atypical clinical and radiological features in some cases, especially in advanced stages of AIDS. Therefore, we need to recognize the characteristics of the clinical and radiological features of the patients with mycobacterial diseases and AIDS.