To evaluate anesthetic experience during open heart surgery, 145 cases of patients under 15kg of body weight from January 1980 to June 1982 were analyzed according to age, sex, technique of anesthesia, anesthetica, premedicants, muscle relaxants, flow rates and mortality. The results were as follows: 1) Premedicants were mainly atropine, meperidine, hydroxyzine, triflupromazine and morphine. 2) Induction agents were thiopental in acyanotic group, but cyanotic group were mainly used ketamine. 3) The inhalation anesthetica that were halothane, methoxyflurane, N@O and enflurane were used in acyanotic group but cyanotic group did not used. 4) Early stage of open heart surgery, gallamine were mainly used but now, pancuronium were used. 5) During cardiopulmonary bypass, the lowest temperature were mean 27 ℃ and flow rate were 80~100ml/kg/m(2). 6) Overall mortality was 17.2%.