Lacunar strokes result from occlusion of penetrating arteries in the deeper, subcortical parts of the cerebrum and brain stem. Approximately 19 percent of all strokes are of the lacunar variety with lacunar strokes representing the most common cerebrovascular complication of chronic hypertension. Four major clinical syndromes are pure motor hemiparesis, pure sensory stroke, ataxic hemiparesis, and the dysarthria-clumsy hand syndrome. The advent of computed tomography (CT) has allowed the antemortem study of lacunar disease and has shed new light on the pathogenesis and clinical course of lacunar strokes. Recently, it has been demonstrated that lacunar strokes may be embolic or hemorrhagic in causation, are not invariably associated with hypertension, and may be larger and associated with hypertension, and may be larger and associated with neurological manifestations that do not conform to the classic patterns. In most instances, however, recognition of the characteristic clinical presentation and confirmation of the diagnosis with noninvasive studies spare many patients unnecessary risks associated with anticoagulation, arteriography, or vascular surgery.