Abstract: Objective: To study the result of cardiopulmonary bypass（CPB）without blood priming in infants and children. Methods: 970 pediatric patients weighing less than 30kg admitted for congenital heart defects were retrospectively studied. They were divided into two groups: 495 of them admitted on Dec.1, 1996 to Nov. 30, 1999 were in group A, while the others admitted from Dec.1, 1999 to Nov. 30, 2002 in group B. Children-special oxygenator SAFEMINI or SAFEMICRO, venous reservoir and circuit were used only in group B, but not in group A. Data were collected including total priming volume, blood transfusion occurrence, and hematocrit before and after the operation. Results: Out of the 495 patients in group A, 113 （22.8%） had used stored blood, while in group B, there were 42（8.8%, P＜0.01）. The total priming volume in group A was greater than in group B. Group B received significantly less stored blood than group A. The ICU stay and modality showed no difference in the two groups（P＞0.05）.Conclusions: We think that the children-special SAFEMINI or SAFEMICRO oxygenator, venous reservoir and circuit play a significant role in reducing the total priming volume. All the above are useful for safe and efficient cardiopulmonary bypass.