It has recently been suggested that most small (<15 mm) subcortical infarcts (SSI) of the centrum ovale (CO) are of lacunar type. We investigated this hypothesis in 255 consecutive patients with a first-ever ischemic stroke who were examined within 24 h after stroke onset and survived on day 10. Fifty-seven patients had CO-SSI: they were older and more likely to have a silent infarct, a lacunar syndrome, arterial hypertension, leuko-araiosis and SSI localized in the basal ganglia or internal capsule and less likely to have a nonlacunar syndrome. On multiple linear regression analysis, independent factors correlated with CO-SSI were the leuko-araiosis score and the presence of a silent infarct, diabetes mellitus and arterial hypertension. However, the presumed cause of the index stroke was large-vessel disease in 7 patients and heart disease in 16. Though we confirm that patients with CO-SSI are more likely to have risk factors for small-vessel disease, a complete diagnostic workup remains necessary in patients with such infarcts because other mechanisms account for one third of them.