Hypertrophic cardiomyopathy (HCM) is a heterogeneous genetic cardiac disorder with various genotypic and phenotypic manifestations, and is often a diagnostic challenge. Although more than forty years have passed since the first description of HCM, a variety of mutations in genes encoding sarcomeric proteins, that cause the disease have been defined by laboratory and clinical studies over the past few years. The fact that HCM is the most common cause of sudden death in young competitive athletes and that, it is actually an important cause of morbidity and mortality in people of all ages, has made the researchers to concentrate more on the molecular basis and treatment strategies of the disease. This study aims to summarize both pathological features and rapidly evolving molecular genetics of HCM, and so to understand this not infrequently seen, complex disorder better.