Objectives: To report the rates of cardiomyopathies in the population below 50 years of age in Qatar. Subjects and Methods: We conducted a retrospective review of clinical data on patients with cardiomyopathy who were hospitalized in Hamad General Hospital, Doha. Data were collected from medical records during the 1996 2002 period and prospectively from the patients who were hospitalized during the year 2003. All cardiomyopathy patients below 50 years of age who were citizens or permanent residents in Qatar were included in this study. Results: During the study period, a total of 132 cases were recorded with idiopathic cardiomyopathies. Among these, 67.4% were males and 32.6% females; Qatari 31.8%, non-Qatari 68.2%. The consanguinity rate was high among Qatari patients. In the first 7-year study period, 1996 - 2002, the incidence rate of all types of cardiomyopathies was 2.5/100,000 population per year (95% CI: 1.4 - 3.5). It increased to 5.2/100,000 population during the year 2003 (95% CI: 3.6 - 6.7). Dilated cardiomyopathy was most prevalent (75.8%) in all age groups, and the incidence increased remarkably with age. Lower prevalence of hypertrophic cardiomyopathy (13.6%) and left ventricle noncompaction cardiomyopathy (6.1%) was found. In children below 15 years of age, the incidence rate for all types of cardiomyopathies was 2.7/100,000 population. The overall mortality rate was 5.3%. Conclusion: Most cases of cardiomyopathy were identified at an early age: below 15 years and above 35 years of age. Introducing preventive and early diagnosis programs may have an impact on reducing the mortality and morbidity from idiopathic cardiomyopathy. Copyright (C) 2006 S. Karger AG, Basel.