We tested the hypothesis that major depression meeting DSM-III-R criteria or medical therapies for depression increase the risk for unprovoked seizures. Major depression was associated with a sixfold increased risk for unprovoked seizures (95% CI, 1.56-22). The risk remained increased even when controlling for age, sex, length of medical follow-up, and medical therapies for depression. In the absence of known prior neurological insult, major depression is associated with an increased risk for unprovoked seizures.