A peptide scanning of the sequences of human herpes virus type 8 (HHV-8) proteins coding orfK8.1 and orf65 was made. The antigenic activity of peptides was evaluated by ELISA. The fragment 101-213 aa of orfK8.1-encoded protein was shown to consist of two sites containing linear B-epitopes that had a weak antigenic activity: 121-145 and 177-209 aa. The protein coding orf65 comprised 2 sites at which linear B-cell epitopes 78-110 aa (a weak antigenic activity) and 142-170 aa (a strong antigenic activity) were located.