Abstract Background Patients with heart failure (HF) have an increased risk of sudden cardiac death, and treatment with an implantable cardioverter defibrillator (ICD) has become standard treatment for selected patient groups. HF is associated with impaired QoL, but there is no consensus regarding the implication of having an ICD. Knowledge regarding QoL in patients with HF and ICD attending follow-up in outpatient HF-clinics is sparse. Purpose The aim of this study was to determine QoL in patients with HF and ICD. Further, to compare QoL in patients with HF with and without ICD, using data from the first and follow-up visits in outpatient HF clinics. Methods Longitudinal data from the National Norwegian Heart Failure Registry (NNHFR), including 9 274 patients, of which 1 206 with an ICD, were studied. QoL was assessed using the Minnesota Living with Heart Failure Questionnaire (MLHFQ). Data was collected at the first and follow-up visits in outpatient HF clinics approximately six months after optimal treatment was achieved. Results Patients with an ICD were younger, more often men, and had higher frequency of coronary artery disease (all p<0.001). At the first visit, there was no significant difference in QoL between patients with and without ICD, with both groups reporting moderate QoL. Both groups had a significant improvement in QoL from the first visit to the follow-up visit (p<0.001). However, patients with ICD reported significantly less improvement in QoL (p<0.001) at follow-up. This disparity was evident regarding both the physical (p<0.001) and the emotional (p<0.001) dimension. Conclusion QoL in patients with HF and ICD improves after follow-up in outpatient HF clinics, although not to the same extent as in patients without ICD. Thus, tailored interventions in outpatient HF clinics may be necessary to improve outcomes in this subgroup of patients with both HF and ICD.