Levosimendan is an inodilator indicated for the short-term treatment of acutely decompensated severe chronic heart failure, and in situations where conventional therapy is not considered adequate. The principal pharmacological effects of levosimendan are (a) increased cardiac contractility by calcium sensitisation of troponin C, (b) vasodilation, and (c) cardioprotection. These last two effects are related to the opening of sarcolemmal and mitochondrial potassium-ATP channels, respectively. Data from clinical trials indicate that levosimendan improves haemodynamics with no attendant significant increase in cardiac oxygen consumption and relieves symptoms of acute heart failure; these effects are not impaired or attenuated by the concomitant use of beta-blockers. Levosimendan also has favourable effects on neurohormone levels in heart failure patients. Levosimendan is generally well tolerated in acute heart failure patients: the most common adverse events encountered in this setting are hypotension, headache, atrial fibrillation, hypokalaemia and tachycardia. Levosimendan has also been studied in other therapeutic applications, particularly cardiac surgery - in which it has shown a range of beneficial haemodynamic and cardioprotective effects, and a favourable influence on clinical outcomes - and has been evaluated in repetitive dosing protocols in patients with advanced chronic heart failure. Levosimendan has shown preliminary positive effects in a range of conditions requiring inotropic support, including right ventricular failure, cardiogenic shock, septic shock, and Takotsubo cardiomyopathy.