Infarcts in the territory of cerebellar arteries, often involving both brainstem and cerebellum, have been well recognized in recent pathological and clinicoradiological studies. To evaluate the situation of pure cerebellar infarcts (PCI) we studied 30 consecutive cases of symptomatic PCI (22 men and 8 women, mean age 58 +/- 17 years) admitted over a 5-year period and selected on the basis of brain computed tomography completed by magnetic resonance in 20 cases and angiography in 15 cases. PCIs accounted for 53 percent of cerebellar infarcts, 10 percent of vertebrobasilar infarcts and 3.2 percent of all cerebral infarcts. The arterial territories involved were the superior cerebellar artery (SCA) in 13 cases (alone in 8 cases), the anterior inferior cerebellar artery in 2 cases, the posterior inferior cerebellar artery (PICA) in 17 cases (alone in 13 cases) and border areas in 5 cases (associated with SCA or PICA). The symptoms were the same in the arterial territories involved (SCA versus PICA), except for dysmetria and vestibular syndrome which were more frequent respectively in SCA territory infarction (P < 0.001) and in PICA territory infarction (P < 0.01). Certain or presumed causes were cardiogenic embolism (23 percent), atherosclerosis (43 percent) and other identified causes, such as oral contraceptives or temporal arteritis (10 percent). They remained undetermined in 24 percent of the cases. Although most patients were severely disabled in the acute stage (Barthel index < 60 in 21 cases), 90 percent recovered subsequently (Barthel index about 100 and 0-2 score on modified Rankin scale). Our findings indicate that symptomatic PCIs are rare; their main causes (cardioembolism and atherosclerosis) do not differ in frequency from those of all cerebral infarcts collected in stroke registries and their functional prognosis is good in almost all cases.