We studied 16 patients with partial epilepsy and drop attacks. The drop attacks appeared 1 to 29 years after onset of epilepsy; 15 patients had these attacks weekly or daily, despite therapy. After the appearance of drop attacks, 6 patients had severe mental disorders, and social life was disrupted in 13. There was a high rate of adversive seizures, atypical absences, and diffuse spike-wave discharges in the EEG, electroclinical features that suggest a frontal origin of epilepsy. Drop attacks are ominous because they occur so frequently, resist therapy, are physically dangerous, and portend personality change.