52 cases of ventricular septal defect [VSD] associated with aortic insufficiency [Al] were found among 1271 patients with simple VSD operated during 27-year period [1959, August-1987, June] at Seoul National University Hospital. Their preoperative data, intraoperative findings and postoperative short-term and long-term follow-up data were evaluated to find the proper timing and method of surgical treatment. The result of this survey shows as follows: 1. To obtain the proper surgical indication, cardiac catheterization and angiography, especially root aortography, was essential. 2. Of all 52 patients, the VSD were type I in 40 patients [77%], type II in 8 [15%] and combination of type I and II in 4 [3%]. Patch closure of VSD were performed in 46 patients and direct suture closure of small VSD in 6. Most common pathologic findings of Al were prolapse of right coronary cusp [40 cases, 77%]. Aortic valve reconstruction were performed in 19 patients, aortic valve replacement in 6 and VSD closure alone in 27. 3. There were 3 surgical deaths [mortality 5.8%], and the long-term follow-up shows that VSD closure alone might have been sufficient to arrest progression of Al in younger patients [less than 10-year old], particularly in those with mild insufficiency. Valve reconstructions, when necessary, were more effective when done at an early age [less than 15-year old]. In a conclusion, we could recommend followings: 1. If patient at any age having VSD with Al is diagnosed, prompt operation is recommended. As for the surgical method, VSD closure only may be fit for mild degree of Al when patient is less than 10-year old, but the management of valve itself may be needed for moderate to severe degree of Al, especially when patient is over 10 year old. The management of valve itself may be variable, but valve reconstruction should be considered as a first choice in less than 15-year old patient. If patient is diagnosed less than 5-year old without evidence of Al, close follow-up observation is recommended. But if Al evidences of clinical findings and/or echocardiography during follow-up examination are notified, corrective operation should be accomplished while the Al is mild. If cusp prolapse and/or even type I VSD of significant size is demonstrated on aortogram, without Al, it should be corrected as early as possible before the patient is about 5 years old.