Comorbidity burden has been linked to survival in patients with an implantable cardioverter-defibrillator (ICD), but no study has examined the influence on psychological well-being and health status. We examined the relationship between comorbidity burden and anxiety, depression, and health status in patients with an ICD during the first 12 months post-implantation using a prospective study design. Consecutively, implanted ICD patients (N 401; 78 men) completed the Hospital Anxiety and Depression Scale and the Short Form Health Survey 36 (SF-36) at baseline, 3, 6, and 12 months post-implantation. Data were analysed using general linear mixed modelling repeated measures multivariable analysis of variance. The mean Charlson comorbidity index score was 3.5 (2.4). In adjusted analyses, comorbidity burden was significantly associated with depression (P 0.003) and the physical health status doma Comorbidity burden was a significant predictor of poorer psychological well-being and physical health status in ICD patients during the first 12 months post-implantation. In the care and management of ICD patients, it is important to recognize the impact of comorbidity burden on patients mood and health status, and that adjunctive intervention may be warranted to enhance well-being.