Background: There are no reports that compared with or without a simultaneous IV infusion in the autologous blood donation of adult patients and pediatric patients in the incidence of vasovagal reactions (VVR) rate. These reactions may decrease return donation and disrupt blood donation activities. Objectives:The purpose of our study is whether we can take autologous blood donation safely from the both groups of adults patients and pediatric patients. To determine whether a IV fluid infusion is required during the autologous blood donation in both of adult and pediatric patients and whether a IV infusion influences the incidence of VVR rate. Study design and Methods: Since 1999, a total of the 922patients (1,654 times donations) were enrolled including 40 pediatric patients: we investigated two groups such as with or without IV infusion. In pediatric patients, their original diseases were almost based on orthopedic disorders. We used exactly same size needle (17.5gage) to the adult and pediatric groups. Results: Ten of 394 times donations in 244 adults patients with the IV infusion group were shown in VVR (2.5%). The other group who had not taken an IV infusion in 375 times donation of 164 adult patients had 1.8% incidence rate of VVR (seven of 375 times donations) during autologous blood donation. There was no significant difference between with or without IV infusion groups of adults. In pediatric patients, one of the ten patients with IV infusion group occurred 10% of VVR and 3 of 30 times donations of without IV infusion occurred same percentage of incident rate (10%). We also investigated what is the risk factor of VVR in pediatric patients. What is the risk factor of pediatric patients? The result was that low hemoglobin data (mean 12.7g/dl vs 14.0g/dl) before donation and below 40kg were high risk groups in VVR incidence (P<0.01). Conclusion: Our study shows that there is no significant change between with or without IV fluid infusion in both groups of patients of adults or pediatrics in autologous blood donation before operations. Therefore it is useful that it can be done safely without IV prevention for VVR, particularly in cases of pediatrics patients.