Extended-release ranolazine (ranolazine ER) [Ranexa(®)] is an antianginal agent that achieves its effects via a novel mechanism of action (inhibition of the late phase of the inward sodium current), without affecting heart rate or blood pressure (BP). This article reviews the efficacy, safety and tolerability of ranolazine ER as add-on therapy in patients with chronic stable angina pectoris, as well as summarizing its pharmacological properties and its use in non-ST-elevation acute coronary syndromes. In the CARISA and ERICA trials, add-on therapy with ranolazine ER improved exercise tolerance and/or reduced angina frequency and nitroglycerin use in patients with chronic stable angina; benefits were seen across a variety of patient subgroups. Although results of the MERLIN-TIMI 36 trial do not support the use of ranolazine ER in the acute management of non-ST-elevation acute coronary syndromes, they do support its use as an antianginal therapy. Ranolazine ER was generally well tolerated, with the most commonly reported adverse events including dizziness, nausea, asthenia and constipation. Despite being associated with modest increases in the corrected QT interval, ranolazine ER demonstrated antiarrhythmic effects in the MERLIN-TIMI 36 trial. In conclusion, ranolazine ER provides an important option for use as add-on therapy to reduce symptoms in patients with chronic stable angina.