HLA A, B, C, typing have been done in 39 patients with clinically and histologically documented classical Kaposi's sarcoma. Thirty three were also typed for HLA DR antigens. Twenty seven were males, 12 were females and three ethnic groups were represented: european caucasoids 41%, north african caucasoids 38.5% and negroids 20.5%. The only statistically significant abnormality is an increase of HLA DR5 frequency (60.6 vs 26. p less than 0.001 et RR = 4.2). Such an increase has been evidenced also in AIDS patients, with or without Kaposi's sarcoma and then is not discriminant between all this different types of the disease.