Clinical, EEG, and autopsy findings were studied in 32 patients with epilepsia partialis continua. The seizures occurred at different ages and with diverse diseases of the brain. Facial and distal limb muscles were preferentially involved. Often, seizures suggested multifocal origin within a limited cerebral region, with low-amplitude, irregular, asynchronous contractions that could resemble other movement disorders. Twitching varied in rate, rhythm, intensity, and territorial extent continued sometimes for decades and was poorly responsive to therapy. Focal EEG abnormalities commonly consisted of discrete spikes, sharp waves, or slow-wave activity. Autopsy findings in eight patients showed consistent involvement of the motor cortex or closely adjacent areas. Clinical, EEG, and pathologic data favor a cortical origin of epilepsia partialis continua.