Introduction. The incidence of mycotic sinusitis in the immunocompetent population has increased in recent decades. This is due to the improvement of diagnostic research, in particular, the new radiographic techniques (CT, MRI) and the increase of conditions that favor fungal infections, corticosteroids and immunosuppressants, radiotherapy, chemotherapy, immunodeficiency disorders. More often in dental practice we will meet with non-invasive maxillary sinus mycosis. The importance of restoring the function of the nasal mucosa after a fungal process is essential in improving the quality of life of our patients. Aim of the study. Analysis of the factors and sources that determine the fungal infection of the maxillary sinuses, effectiveness appreciation of the treatment methods in the maxillary sinuses: Caldwell-Luc radical cure or functional endoscopic surgery. Materials and methods.. The study included 36 patients, 16 men and 20 women, with a mean age of 41.3 years, and between 23 and 70 years of age, with a clinical diagnosis of the micotic sinusitis. All the patients in the study have been endodontically treated of the lateral teeth of the upper jaw. The radiological examination confirmed the diagnosis. In all 36 cases, CTs provided the most comprehensive information. The causal teeth were distributed as following: in 20 patients-d. 15, in 9- d. 26, in 2- d.16 and in other 5- the causal tooth was not established because they were extracted previously. The patients in the study were divided into two groups. The first group consisted of 16 patients, who were operated by Caldwell-Luc method and 20 patients operated endoscopically, who made up the second group. The study groups were compared according to the following criteria: postoperative pain, postoperative edema, length of stay in hospital, need for administration of antibacterial treatment. Results. The Caldwell-Luc method doesn’t allow the release of the natural ostium, therefore the sinus ventilation and drainage are not restored and often relapsed. We determined that no patients in group 2 required analgesic therapy during the postoperative period, while patients in the first group received analgesics 2-5 days. The average length of hospitalization was 5.33 days in patients gr. 1 and 2.5 days- in gr. 2. No patient in gr. 2 had postoperative edema, patients gr. 1 had edema for 4-7 days. In patients gr. 1 was administered antimicrobial treatment, for prophylaxis of postoperative septic complications, but in patients gr. 2 did not need antibiotic therapy Conclusions. Functional endoscopic surgery of maxillary sinus is the gold standard in mycotic sinusitis with predictable results and minimal trauma.