Lacunar infarcts, small deep infarcts that result from occlusion of a penetrating artery, account for about a quarter of all ischaemic strokes. These infarcts have commonly been regarded as benign vascular lesions with a favourable long-term prognosis. However, recent studies have shown that this is only the case early in the disease course. A few years after infarct, there is an increased risk of death, mainly from cardiovascular causes. The risk of recurrent stroke after lacunar infarct is similar to that for most other types of stroke, and patients have an increased risk of developing cognitive decline and dementia. Age, vascular risk factors, high nocturnal blood pressure, and severity of cerebral small-vessel disease at onset have significant prognostic implications for almost all outcomes. More studies on mechanisms, prevention, and treatment are needed to provide specific guidance on the long-term management of patients with lacunar infarcts. Risk-factor modification is likely to play a large part in therapeutic interventions targeted at this stroke subtype.