A 11 year-old girl with quadricuspid aortic avlve associated with regurgitation left superior vena cava and chromosomal anomaly is presented. The quadricuspid valve was unexpectedly found during operation for aortic valve replacement. The aortic valve consisted of 4 equal-sized cusps and retrospective review of the aortogram revealed the aortic valve to have 4 cusps also. To the best of our knowledge, this combination of anomalies has not been reported in Korea previously.