Introduction. Specialists in the field often face uncertainty in deciding whether to perform sinus lifting surgery in the presence of a mucosal cyst during the pre-implantation preparation of patients with maxillary sinus pathology. While some specialists believe that the sinus lifting operation cannot be performed in the presence of sinus pathology and should be resorted to after a long period of healing, others believe that it can be performed in the presence of sinus pathology or simultaneously with sinus sanitation. As a result, there are more controversies about the treatment tactics, stages, and timing required to achieve the rehabilitation of these patients, demonstrating the significance of the problem at hand. Materials and methods. The study included twenty patients who were referred to the Department of OMF Surgery and Oral Implantology “Arsenie Guţan” and the dental clinic “OmniDent” between 20.06.2016 and 01.01.2019 for implant-prosthetic rehabilitation due to partial edentulism in the upper jaw in the lateral area and the presence of a mucosal cyst in the maxillary sinus. The first group comprised of seven patients in whom the mucosal cyst was completely removed while simultaneously undergoing lateral sinus lifting. The second group consisted of five patients, aged between 18 and 67 years (average 45 years), who underwent marsupialization of the mucosal cyst. The third group comprised of six patients in whom the cyst content was only aspirated, without removal or marsupialization of the cyst. Results. All three methods were found to be effective, although total perforations of the sinus mucosa were recorded in the first two groups, preventing the performance of sinus lifting at that stage. The method of aspirating the cystic content, however, is a simple and low-risk procedure that does not carry the risk of perforating the sinus membrane and provides predictable results. Conclusions. The mucosal cyst does not present a contraindication to sinus lifting but requires additional surgical procedures.