Background: Continuing warfarin therapy is considered safe for patient undergoing pacemaker or implantable cardioverter defibrillator procedures, but less evidence exists for patients undergoing cardiac resynchronization therapy (CRT) device implantation. Subjects and Methods: We retrospectively evaluated 136 consecutive patients who received a CRT device. Three periprocedural anticoagulation strategies were utilized: Group 1, continuation of therapeutic warfarin; Group 2, cessation of warfarin with heparin bridging; and Group 3, cessation of anticoagulation temporarily. Groups were compared on the incidence of complications. Results: Of the 136 patients, 87 (64%) were in Group 1, 18 (13%) were in Group 2, and 31 (23%) were in Group 3. Group 1 patients had an international normalized ratio of 2.3 ± 0.5, which was significantly higher than the other two groups. Coronary sinus dissection occurred in four patients: Three in Group 1 and one in Group 2, but no patient experienced pericardial effusion or tamponade. Group 2 experienced a higher incidence of pocket hematoma (P = 0.0065) and a longer length of hospital stay (P = 0.0069) than Group 1. Transient ischemic attack occurred in one patient in Group 3. Conclusion: Continuing warfarin with therapeutic international normalized ratio seems to be safe in individuals undergoing CRT device implantation.