Mechanical heart valves are associated with high risk of thrombosis and thromboembolic complications. Vitamin K antagonist is the only approved oral medication for the anticoagulation in cases of mechanical heart valves. This poses a challenge in cases where vitamin K antagonists are contraindicated. Although temporary anticoagulation with low molecular weight heparin is common among pregnant patients with mechanical heart valves, data about long term anticoagulation with low molecular weight heparin is limited. We report a successful long-term anticoagulation with low molecular weight heparin in a patient with mechanical mitral valve and atrial flutter.