Two cases of lacunar infarction of "ataxic-hemiparesis" type secondary to luetic vasculitis are presented. The first patient presented meningovasculitis and the second progressive general paralysis. In both cases the ischemic lesion was seen by magnetic resonance and was located at a pontine level in one case and in the corona radiata in the other. Treponemal serology in plasma and CSF was positive in both cases with lymphocytic pleocytosis and high CSF protein levels being observed. Clinical and response to treatment was satisfactory except in the case of general paralysis in whom the impairments existing prior to the cerebral infarction persisted. This study complements recent communications in which neurosyphilis was attributed to the appearance of other lacunar type infarctions (pure motor hemiparesis).