Nocturnal leg cramps are common and troublesome, especially in later life, and have a significant impact on quality of life, particularly sleep quality. This article reviews the current state of knowledge regarding the diagnosis, frequency, pathophysiology and management of cramps. Recent evidence suggests that diuretic and long-acting beta-agonist therapy predispose to leg cramps. There is conflicting evidence regarding the efficacy of prophylactic stretching exercises in preventing cramps. Quinine remains the only medication proven to reduce the frequency and intensity of leg cramps. However, the degree of benefit from quinine is modest and the risks include rare but serious immune-mediated reactions and, especially in older people, dose-related side effects. Quinine treatment should be restricted to those with severe symptoms, should be subject to regular review and requires discussion of the risks and benefits with patients.