Antibodies to negatively charged phospholipids including cardiolipin have been recognized in the sera of patients with systemic lupus erythematosus and other disorders. We report 4 patients who experienced cerebral infarctions and dementia in association with anticardiolipin antibodies. These patients did not have the characteristic lupus anticoagulant or systemic lupus erythematosus. The occurrence of anticardiolipin antibodies in patients with multiple cerebral infarctions who do not have evidence of a systemic vasculitis or inflammatory condition suggests that this association may be more common than previously recognized. It may be useful to test for the presence of anticardiolipin antibodies in patients who have unexplained cerebral infarctions.