Background Patient-reported health-related quality of life is increasingly used as an outcome measure in clinical trials and as a performance measure to evaluate quality of care. The objective of this study was to assess the psychometric properties of the Danish HeartQoL questionnaire, a core heart disease-specific health-related quality of life questionnaire, in implantable cardioverter defibrillator recipients. Design This study involved cross-sectional and test-retest study designs. Method Implantable cardioverter defibrillator recipients in the cross-sectional study completed the HeartQoL, the Short-Form 36 Health Survey, and the Hospital Anxiety and Depression Scale. The HeartQoL structure, construct-related validity (convergent and discriminative) and reliability (internal consistency) were assessed. HeartQoL reproducibility (test-retest) was assessed in an independent sample of implantable cardioverter defibrillator recipients. Results Mokken scale analysis supported the bi-dimensional structure of HeartQoL among 358 implantable cardioverter defibrillator recipients. Convergent ( r > 0.72) and discriminative validity were confirmed. The HeartQoL scales demonstrated satisfactory internal consistency (Cronbach's alpha > 0.90). Test-retest reliability (two weeks interval) was assessed in 89 implantable cardioverter defibrillator recipients and found to be acceptable for each scale (intra-class correlation > 0.90). Conclusion The Danish HeartQoL questionnaire demonstrated satisfactory key psychometric attributes of validity and reliability in this implantable cardioverter defibrillator population. This study adds support for the HeartQoL as a core heart-specific health-related quality of life questionnaire in a broad group of patients with heart disease including implantable cardioverter defibrillator recipients.