Hypertrophic cardiomyopathy (HCM) is a genetic disease of the sarcomeric contractile proteins that is characterized by left ventricular hypertrophy and myocyte disarray. The majority of patients are limited in terms of functional capacity and a minority die suddenly. The main aims of management are symptom alleviation and prevention of sudden cardiac death. In patients with HCM, cardiopulmonary exercise testing provides a more accurate index of functional capacity than New York Heart Association classification status and is useful in assessing symptoms following various therapeutic interventions. Cardiopulmonary exercise testing plays an important role in differentiating HCM from other conditions associated with left ventricular hypertrophy. Cardiopulmonary exercise testing is also valuable in identifying individuals at high risk of sudden cardiac death and is an integral part of the algorithm in risk stratification and delivery of prophylactic therapy. Over the past few years, cardiopulmonary exercise testing has provided insight into the determinants and mechanisms of exercise limitation. This understanding helps in targeting therapy and the development of new treatment modalities.