Abstract Background Sarcoidosis, a systemic inflammatory disorder, can manifest as progressive inflammatory heart disease, termed cardiac sarcoidosis (CS). Despite advances in treatment, the impact of CS on health-related quality of life (HRQoL) remains incompletely understood. This study aimed to compare HRQoL between patients with CS and those with non-inflammatory cardiomyopathies, namely dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM). Purpose To assess and compare HRQoL across patients with cardiac sarcoidosis and non-inflammatory cardiomyopathies. Methods A total of 240 CS patients (86% response rate), 96 DCM patients (55% response rate), and 81 HCM patients (65% response rate) completed the RAND-36 general health-related questionnaire, comprising eight dimensions. Patients listed for transplantation were excluded. Clinical data were obtained from the Finnish myocardial inflammatory diseases registry for CS patients and from medical records in hospitals for HCM and DCM patients. Results Median age ranged from 56 to 59 years across the groups. Unlike DCM, which typically presents with heart failure symptoms, a substantial proportion (82%) of CS patients presented with advanced atrioventricular block or ventricular arrhythmias, while HCM cases were often incidentally detected or identified through family screening. Most CS patients (94%) had implanted pacemakers or ICDs, compared to a lower proportion in HCM (26%) and DCM (63%). DCM patients exhibited a higher prevalence of impaired LVEF (<50%) compared to CS and HCM patients. Functional impairment, as measured by NYHA class, was most pronounced in DCM patients. CS patients experienced more adverse events between diagnosis and the study entry, particularly sustained ventricular tachycardia/ventricular fibrillation. However, heart failure hospitalizations did not significantly differ between groups. Table 1 presents a comparative analysis of patient-reported outcomes across four functional and mental dimensions to assess the relative burden of disease among patients with CS, HCM, and DCM. While the functional dimensions in CS exhibited disparities from both HCM and DCM, no significant differences were observed in the mental dimensions between CS and HCM. CS patients reported lower scores in the domains of role physical, and general health compared to either HCM or DCM counterparts. Conclusion Patients with CS demonstrated significantly poorer HRQoL compared to those with non-inflammatory cardiomyopathies. This underscores the substantial burden of disease associated with CS and highlights the importance of comprehensive management strategies to address both clinical and quality of life aspects in affected individuals.