Economic efficiency has recently been required even in public hospitals. Medical fees from health insurance account for most of the medical income of our hospital. Medical fees were counted in units of points, with one point equaling 10yen. However, it is unclear how many points are omitted in determining medical fees to be paid by health insurance. This study investigated the extent of such omissions.The subjects were all outpatients who consulted the Department of Otolaryngology of Takarazuka Municipal Hospital between January 24 and 28, 2005. Following the completion of daily work, we examined the slip sheets actually used to calculate payments and determined the omissions. In our department, when a doctor completes the treatment and/or examination, the nurse checks the appropriate items in slip sheets.Omissions were found on slip sheets for 40 of 372 patients (10.8%). Based on the total reward receipts (322, 988 points), 5298 points (1.6%) had been omitted. Omissions for balance tests, middle ear fiberscopy and laryngoscopy were particularly common.The loss associated with this were estimated as about 2, 360, 000yen annually. The reason for omissions appeared to be the lack of presence of a nurse during treatment and/or examinations and poor knowledge of nurses about otolaryngological care.