Objectives. Data quality is a prerequisite for the use of registries. National Registry for Ablation and Electrophysiology in Norway (AblaNor) is a nationwide medical quality register of Norwegian patients undergoing electrophysiology (EP) examination and ablation. The aim of this study is to assess the coverage of registrations and completeness and reliability variables in AblaNor. Design. National coverage was assessed by comparing EP patients registered in the Norwegian Patient Registry (NPR) and AblaNor in 2021. Completeness of AblaNor registrations was calculated by examining fraction of missing data in key variables. To study reliability, 13 dummy patients were invented and distributed to electrophysiologists in all five EP-centres in Norway. Interrater reliability between the five ratings was assessed for categorical variables by calculating observed percent agreement (PA), Gwet's agreement coefficient (AC1, AC2) and Krippendorff's alpha (K alpha) coefficient. The intraclass correlation coefficient (ICC) was calculated for continuous variables. Results. National coverage was high (93%) with excellent variable completeness (99%). Most variables showed almost perfect (AC1 0.8) or substantial (AC1 0.61-0.80) reliability. Conclusions. Data in AblaNor shows very good national coverage and completeness of data, with a high degree of reliability for most variables.