Aim. The obtaining of bioaffinity sorbent based on the immobilized protein A of S. aureus (SPA) using two cellulose-binding domains (CBD), and its application for purification of antibodies. Methods. The DNA sequences encoding SPA and two CBD were genetically fused, expressed in the high-productive Escherichia coli system and the protein SPA-CBD2 was obtained in a soluble form. The SPA-CBD2 fusion protein was affinity immobilized on the microcrystalline cellulose. Results. Capacity of bioaffinity sorbent (1 mg SPA-CBD2/1 ml CC31-cellulose), dynamic capacity (3 mg mouse IgG/1 ml bioaffinity sorbent), efficiency and stability during prolonged storage were determined. The bioffinity sorbent was used for purification of antibodies. The purity of antibodies in eluted fractions was more than 95 %. The purified antibodies detected target antigens with a high sensitivity. Conclusions. The designed bioaffinity sorbent provides obtaining pure poly- and monoclonal antibodies in functionally active form and can be useful for the fractionation of mouse immunoglobulin G.