Purpose Wrong-site surgeries are rare but potentially serious clinical errors. Marking the surgical site is crucial to preventing errors, but is hindered in the ENT field by the presence of many internal organs. In addition, there is no standardized marking procedure. Methods Here, an ENT surgical-marking procedure was developed and introduced at a clinic. The procedure was evaluated through anonymized questionnaires. This study was conducted over a 6-month period by interviewing patients and, at the beginning and end of this period, doctors and other surgical staff. Results The internal organ-marking problem was solved by applying a fixed abbreviation for each procedure onto the shoulder in addition to marking the skin surface as close to the organ as possible. The procedure was described as practicable by 100% of the interviewees; 75% of the ENT physicians and 96.3% of the other surgical staff considered the procedure highly important for preventing site confusion, and 75% of the physicians had a consequently greater feeling of safety. Of the 248 patients surveyed, 96.0% considered the marking procedure useful, and 75.8% had a consequently greater feeling of safety. For 52.0%, the marking reduced their fear of the operation. Conclusions For the first time, a standardized procedure was developed to mark the site of ENT surgery directly, uniformly and safely on patients. The procedure was judged to be useful and practicable and was also deemed crucial for preventing site confusion. Patients felt safer and less fearful of the operation due to the marking.