A clinical trial was made of two types of laryngeal endoprostheses in surgery of stenosis caused by benign diseases. A total of 15 patients were operated on. In 11 patients endoprosthesis of biocompatible polymers was inserted, in 4 patients the stenosis was corrected with endoprosthesis of silicon rubber. Most of the patients had stenosis as a result of complication of thyroid surgery. The operative technique is described. In extensive defects of the anterior wall of the larynx and trachea, advanced scar stenoses a new operation is proposed-autoalloplasty using body and manubrium of the sternum.