To this day, chronic rhinosinusitis remains the most common pathology that otorhinolaryngologists face on a daily basis. In the Russian Federation, the prevalence of chronic rhinosinusitis is about 15%, and maxillary sinusitis of odontogenic etiology accounts for 10% to 12% of all chronic inflammatory processes of the maxillary sinus. Long-term conservative therapy based on the systemic use of antibacterial drugs is usually not effective and only temporarily relieves the condition of a patient with maxillary sinusitis, but does not cure it completely. Alternative treatment methods include a course of maxillary sinus punctures with the introduction of antiseptic/antibacterial drugs (in order to evacuate the pathological contents and local effect on the inflammation site) or the installation of a catheter into the sinus lumen during the primary puncture (for the purpose of further daily sinus flushing and administration of antiseptic drugs). Data on the effectiveness of such methods of treatment of chronic odontogenic maxillary sinusitis were not found in the research descriptions at the time of the presentation of the clinical case.