Background: Development of many techniques conserve blood in cardiac surgery has been established, to avoid the side effects of homologous blood transfusion. One of these techniques is the Retrograde Autologous Priming (RAP); which is a blood conservation technique designed to decrease the severity of hemodilution during cardiopulmonary bypass and thus decreasing perioperative transfusions. Aim of Study: The aim was to examine the safety and efficacy of RAP and its role in decreasing adverse outcomes on body systems after cardiac surgery. Patients and Methods: This work was performed on 60 adult patients indicated for open heart surgery as valvular heart disease or coronary heart disease. 30 patients were operated using RAP technique and 30 patients using ordinary priming method of cardiopulmonary bypass (CPB). Results: The CPB mean time was significantly shorter in the RAP group. The hemoglobin (Hb) level and hematocrit (Hct) concentration in the perioperative and postoperative time as significantly higher in the RAP group also the platelet count was significantly higher in the RAP group (p<0.05) with decreased incidence of post-operative bleeding in the RAP group. Also, there was significant reduction in the incidence of post-operative liver affection; there was no statistically significant difference in postoperative renal, pulmonary and neurological complications (p>0.05) between the two groups. Conclusions: RAP is an efficient and economical method in limiting the amount of priming volume of the CPB system, causing less hemodilution, reducing intra- and postoperative blood transfusion and decreasing adverse effects of hemodi-lution on body systems.