Since 1989 we have been using on a regular basis in our department endoscopic technics applied to fosas and paranasal sinuses. A methodological study of the first 100 cases of this type of surgery is presented. The indications, results, and complications of the surgical technique are analyzed. The cases included: sinusitis, nasosinusal polyposis, endoscopy of malignant tumors, epistaxis, various inflammatory processes, and plastic endonasal reparations. It is concluded that nasosinusal endoscopic surgery is an advantageous technique in the treatment of general nasosinusal conditions.