Heparin is the anticoagulation of choice for cardiac surgery requiring cardiopulmonary bypass. Heparin resistance (HR) is inability to achieve ACT > 400s inspite of administering high dose of heparin. Causes for HR include antithrombin deficiency, increased heparin binding proteins, prior heparin exposure, platelet activation, medications like Nitroglycerin, increased heparin clearance, high levels of factor VIII and factitious heparin resistance. It can be managed with FFP or antithrombin concentrates to increase the levels of AT. Alternate anticoagulants like direct thrombin inhibitors and factor Xa inhibitors were also successfully used for anticoagulation during CPB, but the risk of thrombosis remains high. We hereby report a case of a 40 year female who developed heparin resistance during CPB for mitral valve replacement which was successfully managed with transfusion of FFP.