Background: Cardiopulmonary bypass (CPB) is known to cause an inflammatory response and activate some mediators that could affect hemostasis, also can cause haemodilution and anemia, that could be claimed as factors lead to post-operative nonsurgical bleeding. Modified Ultrafiltration (MUF) considered as new strategy to mitigate inflammatory response and help to haemoconcentrate the blood of the patients without blood transfusion, and so decrease post cardiac surgery bleeding. Methods : A randomized control prospective study run over 200 patients underwent cardiac surgery in ALHADA Military Hospital between December 2008 till December 2012, patients were divided randomly into two groups ; MUF with conventional ultrafiltration as study group and conventional ultrafiltration as control group, chest tube drainage post-operative was calculated over the first 48 hours, to evaluate the effect of using MUF in decreasing the risk of post cardiac surgery bleeding, results were expressed in term of percentages , means and p value (p