Aim. The objective of the present study was to evaluate the effectiveness of the treatment of chronic odontogenic maxillary sinusitis with the use of the replantation technique. Patient A. aged 45 years applied for the medical aid to a stomatological polyclinic with the complaint of the aesthetic defect in the dental filling (teeth 2.4 and 2.5). The results of analysis of the medical history and the objective investigation provided materials for the diagnosis of left-side chronic odontogenic maxillary sinusitis and the periapical (radicular) cyst of teeth 2.4 and 2.5. Replantation of teeth 2.4 and 2.5 was offered to the patient. The root fracture of tooth 2.4 occurred during the surgical intervention; as a result only tooth 2.5 was replanted. Results. The X-ray study on day 150 after replantation of tooth 2.5 revealed the periodontal ligament space. The tooth was immobile and percussion painless. The muco-gingival junction was well-defined and remained non-hyperaemic. The examination with the use of cone beam computed tomography (CBCT) has demonstrated that the area of the bone defect with the density below 350 HU evaluated based on the Hounsfield unit scale decreased by 23%. The measurements of pneumatization of the left maxillary sinus gave evidence that it was filled with the air. Conclusion. The reported clinical case confirms the effectiveness of replantation as an approach to the treatment of chronic odontogenic maxillary sinusitis .