A statistical analysis on 705 operated cases (650 admitted patients) at our clinic during the period of 1 year from August 1974 to July 1975. The following results were obtained. 1) The admission rate was 6.2 percent and operation rate was 5.8 percent of total patients. 2) The highest incidence in age distribution was the second decade (30%) and followed by the third decade (17%) and sex distribution was higher in male (63%) than female (37%) with a ratio 1.7 to 1. 3) The highest incidence was observed in Jan. in monthly distribution and winter in the seasonal distribution. 4) The operation distribution was so follows ; Head and neck op. 184 cases (26%) ; Otologic op. 104 cases (15%) ; Plastic and reconstructive op. 58 cases (8%) ; Endoscopic op. 122 cases (17%) ; General op. 237 cases (34%). a) The most frequent operation in head and neck field was tracheotomy (20 cases) and followed by the total maxillectomy (15 cases). b) The most frequent op. in otologic field was tympanoplasty and mastoidectomy (82 cases) and followed by the modified radical mastoidectomy (8 cases). c) The most frequent op. in plastic and reconstructive field was tracheoplasty (12 cases) and repair of cleft palate (12 cases). d) The most frequent op. in endoscopic field was esophagoscopy (65 cases) and followed by the laryngoscopy (54 cases). e) The most frequent op. in general field was antrotomy (75 cases) and followed by the tonsillectomy (60 cases).