The process of mitochondrial dynamics is emerging as a core player in cardiovascular homeostasis. This process refers to the co-ordinated cycles of biogenesis, fusion, fission and degradation to which mitochondria constantly undergo to maintain their integrity, distribution and size. These mechanisms represent an early response to mitochondrial stress, confining organelle portions that are irreversibly damaged and preserving mitochondrial function. Accumulating evidence demonstrates that impairment in mitochondrial dynamics leads to myocardial damage and cardiac disease progression in a variety of disease models, including pressure overload, ischaemia/reperfusion and metabolic disturbance. These findings suggest that modulation of mitochondrial dynamics may be considered as a valid therapeutic strategy in cardiovascular diseases. In this review, we discuss the current evidence about the role of mitochondrial dynamics in cardiac pathophysiology, with a particular focus on the mechanisms underlying the development of cardiac hypertrophy and heart failure, metabolic and genetic cardiomyopathies, ischaemia/reperfusion injury, atherosclerosis and ischaemic stroke.