42 patients (33 males and 9 females) with chronic active hepatitis (CAH) mostly HBsAg+, were typed for 24 alleles of the A and B loci. Diagnosis was performed according to the criteria outlined by the European Association for the Study of the Liver. The increased frequency of HLA-A3 (47.6 % instead of 19.1 % in 266 healthy controls) is significant after correction. The relative risk is 3.83. The phenotypic association A3/Bw35 is also increased (28.5 % instead of 6.0 in the control group). The risk of the A3/Bw35 association is 6.25. The risk of A3 calculated in patients lacking Bw35 is 1.6. A family study in 5 patients over 5 showed an haplotype A3/Bw35.