Patients on long-term anticoagulation who require interruption of therapy for surgery may receive "bridging therapy" with continuous-infusion unfractionated heparin or low-molecular-weight heparin (LMWH). We estimated the costs of bridging therapy with: (1) LMWH self-administered at home, (2) LMWH administered by a nurse to patients at home, and (3) continuous-infusion unfractionated heparin in the hospital. For surgeries requiring an overnight stay, bridging costs are estimated to be 672, 933, and 3,816 US dollars, respectively, for each of these strategies.