Cardiomyopathies are responsible for heart failure and sudden cardiac death, but epidemiological data are scarce and the public health burden may be underestimated. We studied aggregating data from all public or private hospitals in France. Patients were categorized from relevant ICD-10 codes into dilated, hypertrophic, restrictive, or other cardiomyopathies (DCM, HCM, RCM, or OCM, respectively). Between 2008 and 2015, a total of 326,461 distinct patients had cardiomyopathy-related hospitalizations. The hospital-based prevalence of cardiomyopathy was 809 per million inhabitants (PMI) per year, including 428 PMI for DCM, 101 PMI for HCM, 26 PMI for RCM, and 253 PMI for OCM. Patients with cardiomyopathies accounted for 51% of all heart transplants, 33% of defibrillator implantations, 38% of mechanical circulatory supports, and 11.3% of hospitalizations for heart failure. In patients less than 40 years of age, these figures were 71%, 51%, 63%, and 23%, respectively. Over 2008-2015 and considering all cardiomyopathies, there was a significant increase for heart transplant (average annual percentage change, AAPC: +3.86%, p = 0.0015) and for defibrillator implantation (AAPC: +6.98%, p < 0.0001), and a significant decrease of in-hospital mortality (AAPC: -4.7%, p = 0.0002). This nationwide study shows that cardiomyopathies constitute an important cause of hospitalization, with increasing invasive therapeutic procedures and decreasing mortality.