The purpose of the study was to give a clinical evaluation of the effectiveness of endonasal blockade of the nasopalatine nerve in different ways during radical maxillary sinusotomy in dental patients. Materials and methods. Clinical observations were performed in 50 patients diagnosed with chronic odontogenic maxillary sinusitis. Radical maxillary sinusotomy was performed under local potentiated anesthesia. All patients underwent anesthesia on the maxilla according to classical methods. Patients, depending on the methods of endonasal blockade of the nasopalatine nerve, were divided into two clinical groups: the main (24 people) and the comparison group (26 people). Patients of the main group underwent endonasal blockade of the nasopalatine nerve at the site of its branch from the pterygopalatine ganglion. In patients of the comparison group, the blockade of this nerve was performed before its entry into the incisal canal. The effectiveness of anesthesia was evaluated for clinical and autonomic manifestations of pain stress. Results and discussion. During the removal of polyps and pathological granulations from the mucous membrane of the maxillary sinus in patients of the main group there was no pain, no emotional-motor and autonomic manifestations of pain stress, which confirmed the effectiveness of the endonasal method of anesthesia of the nasopalatine nerve. In patients of the comparison group during similar surgical manipulations the full effect of local anesthesia was achieved in 50.0% of cases (χ2 – 8.065, р = 0.005). These were patients who had hypopneumatized or moderately pneumatized types of maxillary sinuses. The rest of the patients during the operation had emotional – motor and autonomic manifestations of pain stress during the removal of pathologically altered mucous membrane located on the medial wall of the maxillary sinus. Conclusion. Complete anesthesia of the mucous membrane, maxillary sinus, regardless of the degree of its pneumatization is achieved during the usage of endonasal blockade of the nasopalatine nerve at the site of its branch from the pterygopalatine ganglion during radical maxillary sinusotomy in dental patients. Anesthesia of the nasopalatine nerve in the lower nasal passage, before its entry into the incisal canal, allows painless surgery only in patients with hypopneumatized maxillary sinuses and in most patients with moderate pneumatization