Hypertrophic cardiomyopathy (HCM) is the commonest inherited cardiovascular disorder with a prevalence of one in 500 in the general population. It is believed to be a disease of the cardiac sarcomere and is caused by a variety of mutations in genes responsible for sarcomeric contractile proteins. It is characterised macroscopically by myocardial hypertrophy and microscopically by myocyte fibrosis and disarray. Most patients tend to present with functional limitation and symptoms such as palpitation, chest pain or syncope. The underlying mechanisms involved are complex, multiple and not yet fully understood. Further clarification of these mechanisms may enable improvements in current symptom control or the development of new avenues of therapy. A small but significant proportion of patients suffer sudden cardiac death and this can be the initial presentation of the condition. In fact, HCM is the commonest cause of sudden death among individuals below the age of 30 years. The identification of this high-risk cohort remains the most important aspect of HCM management, particularly in light of growing evidence of the effectiveness of prophylactic strategies.