Authors analyzed clinical findings of 217 patients(364 ear) with middle ear effusion who were taken myringotomy and ventilation tube insertion during the period of July, 1979 through December, 1983 at Wallace Memorial Baptist Hospital in Busan. The results were as follows ; 1) The sex distribution showed 116 male(53%) and 101 female(47%). 2) The age distribution was most common in the ages from 6 to 10(98 cases, 45%). 3) Bilateral effusion was 68% and unilateral effusion was 32%. 4) The nature of Middle Ear Effusion(M.E.E.) was 47% serous exudate, 38% mucoid exudate, 5% purulent, 2% bloody, and 9% scanty or no fluid. 5) In the preoperative tympanogram, there were 6% with type A, 91% with type B, and 3% with type C. 6) The number of paients who had past history of myringotomy and ventilation tube insertion were 18 cases among the recent 122 M.E.E. cases. 7) The postoperative average hearing gain was 17.0dB.