Background: Cardiopulmonary Bypass (CPB) application may cause severe hemodilution and an acute systemic infl ammatory response syndrome, especially with blood components transfusion. Multi-function circuit of cardioplegia delivery, conventional ultrafi ltration, and modifi ed ultrafi ltration was advocated to reverse the CPB hemodilution and conserve patient's blood through a blood conservation protocol. Methods: Retrospectively, 600 pediatric were randomly and equally distributed into six studied (S) and control (C) groups. Groups had been classifi ed according to weights as following; 30 kg≥ groups IS and IC >20 kg≥ groups IIS and IIC >10 kg≥ groups IIIS and IIIC ≥3kg, only studied groups were treated with the blood conservation protocol. The fl uid management, blood components conservation, and pediatrics clinical outcome characteristics will be investigated in this study. Results: 100% achievements for zero fl uids balance and bloodless surgery for studied pediatrics of weights ≥6 kg with signifi cant autotransfusion amounts of RBCs, plasma and total protein (p<0.02). Studied pediatrics of weights <6 kg received a signifi cantly lesser amount of homologous packed red blood cells, fresh frozen plasma, platelets (p<0.05) and protein product (p<0.01) compared with control pediatrics. Studied groups showed a gradual increase in mean arterial pressure during modifi ed ultrafi ltration process, with signifi cant lesser collectively total dopamine dose (p<0.05 and p<0.02 for weights range of 30-6 kg and <6 kg respectevely). Signifi cant lower blood loss (p<0.01) and shorter intubation duration and ICU stay (p<0.05 for group IS and p<0.01 for groups IIS and IIIS) observed for the studied groups. Conclusion: The blood conservation protocol under investigation is a successful method using routine CPB unit components facilitating bloodless surgery for pediatric weights range of 6-30kg.