INTRODUCTION: The aim of this investigation was to determine additional predisposing factors of pocket hematoma formation in patients undergoing anti-arrhythmic device surgery. METHODS: Initially, we performed a retrospective chart review of 459 patients on warfarin therapy who underwent anti-arrhythmic device surgery (pacemaker or defibrillator implantation, generator replacement, or lead revision) between April 2004 and September 2008 to determine whether continuation of anticoagulation or cessation of anticoagulation, with or without bridging therapy, was the preferred approach. In those patients who developed pocket hematoma, we then analyzed factors that might predispose to hematoma formation. RESULTS: The incidence of pocket hematoma in the entire group was 2.2% (n = 10). Forty-eight percent of the patient group was on continued warfarin (n = 220), 27% on bridging therapy with intravenous heparin or subcutaneous enoxaparin (n = 123) and 66% were on antiplatelet therapy (aspirin or clopidegrol or both; n = 303) at the time of device implantation. Twelve percent of the patients had chronic kidney disease (n = 55). In multivariate regression analysis, after adjusting for anticoagulation and antiplatelet agents, chronic kidney disease was found to be a significant risk factor for pocket hematoma formation after ICD and pacemaker placement. An increase of 1.0 mg/dl in creatinine levels was associated with a nearly twofold increase in hematoma formation (OR, 1.99; 95% CI, 1.22-3.21; p = 0.03). CONCLUSION: Chronic kidney disease is a significant risk factor for pocket hematoma formation after pacemaker and ICD placement, independent of anticoagulation and antiplatelet agents.