Seizures occurred in 19 of 112 patients (17%) with nontraumatic, supratentorial intracerebral hemorrhage (ICH). All seizures occurred at ICH onset; patients without seizures at hemorrhage onset remained seizure-free until the last recorded follow-up. Seizures were significantly associated with extension of blood into the cerebral cortex. We found no association between seizures and hemorrhage size or the presence of subarachnoid or intraventricular blood. These data suggest that (1) seizures, in ICH, occur at hemorrhage onset, (2) patients without seizures at hemorrhage onset are at very low risk for subsequent seizures during their hospitalization, (3) hemorrhage involving the cerebral cortex, regardless of site of origin, predisposes to seizures, and (4) the prophylactic use of anticonvulsants in the acute management of these patients appears unwarranted, especially in patients without cortical extension.