Hypertrophic cardiomyopathy (HCM) is a cardiac muscle disease with characteristic (mostly asymmetrically distributed) hypertrophy of a non-dilated left ventricle in the absence of another cardiac or systemic disease that can cause left ventricle hypertrophy. The prevalence of HCM in the general population is estimated to be 1 in 500 persons. It is an inheritable disease of the heart with a heterogeneous expression and a great diversity of morphological, functional and clinical features. The genes involved code for components of a large protein complex ('the sarcomere'), which ensures the contraction of the cardiac muscle. Electrocardiography, echocardiography and cardiac MRI play a role in the diagnosis. Medicinal treatment can improve the diastolic filling and the ventricle function. In addition to this there are surgical and non-surgical possibilities for myocardial reduction. For patients with life-threatening arrhythmias and for the primary prevention of sudden death for high-risk patients, an internally implantable cardioverter-defibrillator is indicated. The early detection of patients with a predisposition for HCM is only possible by means of genotyping.