Objective: development and efficacy assessment of the tactic of actions in reverse shoulder arthroplasty in bone mass defects and deficiency of the scapular glenoid fossa. Materials and Methods. At the Division of Adult Orthopedics, N.N. Priorov National Medical Research Center of Traumatology and Orthopedics, Ministry of Healthcare of the Russian Federation, 6 patients with glenoid bone mass deficiency were subjected to the reverse shoulder arthroplasty: 4 of those received the replacement of marginal bone defects, whereas 2 subjects underwent the replacement of extensive bone defects. Results. During the follow-up period of the operated patients, which lasted 6-24 months, good clinical, radiological and functional results were obtained. There were no intraoperative or postoperative complications. Conclusion. The proposed replacement method of glenoid defects in reverse arthroplasty exhibited high efficacy.