AIMS To investigate the different strategies adopted for the management of antithrombotic therapy and the related hemorrhagic and infective complication rates in patients undergoing cardiac implantable electronic devices (CIEDs) surgery in a real-world setting. METHODS THE Management of AntiThrOMbotic therApy in patients undergoing electrophysiological device surgery: Italian NatiOnal Multicenter Observational REgistry (HEMATOMA NO MORE) is an observational, prospective, multicenter, national cohort study (with a retrospective, multicenter, regional pilot phase) designed to enroll patients with standard indications to CIED implantations/replacements receiving concomitant antithrombotic therapy. The primary outcome is clinically significant pocket hematoma defined as a postprocedural hematoma, resulting in prolonged hospitalization and/or requiring interruption of antithrombotic therapy and/or requiring further surgery and/or requiring transfusion. RESULTS The pilot phase included 569 patients from 11 centers in Tuscany enrolled between September 2014 and May 2015 and followed up for 1 month. Patients were categorized according to the strategy of management of antithrombotic therapy, with heparin bridging being associated with the highest incidence of clinically significant pocket hematoma (12.3%). Overall nonpocket hemorrhagic events rate was quite low (0.52%) and thromboembolic complications were negligible (0.17%). CONCLUSION Occurrence of pocket hematoma in patients undergoing CIED surgery is largely influenced by the strategy of management of antithrombotic therapy. The HEMATOMA NO MORE will assess the impact of different strategies on the risk of developing pocket hematoma and of subsequent CIED-related infections.