The evolution of 1.217 epileptic patients submitted to antiepileptic drug treatment is studied. Barbiturates, hydantoin, primidone and trimethadione were administered to the patients, isolated or in association. The study was made in regard to the clinical manifestations and electroencephalographic pattern. Concerning the type of seizures, the author draws the following conclusions : 1) the evolution was better in patients with Bravais-Jackson seizures; 2) the highest percentual rate of remission was shown by patients with sleep seizures (59,0%); 3) the patients with "grand mal" seizures without aura were the most refractory to the treatment; 4) the patients with generalized fits secondary to focal discharges showed the best results, although evidencing lowest remission index; 5) among all types of seizures, the Bravais-Jacsonian fits showed better evolution, specially the cases without generalization; 6) significant differences of evolution were not found between convulsive and non convulsive epilepsy. The electroencephalographic study led the author to the following conclusions: 1) the evolution was better in cases with normal EEG; 2) the evolution was better in cases with paroxystic, bilateral and synchronic dysrhythmia than in cases with diffuse abnormalities in sensu latu and with focal abnormalities; 3) the patients with temporal dysrhythmia showed the lowest remission index; 4) the patients with unilateral temporal dysrhythmia showed better evolution than those with bilateral temporal dysrhythmia; 5) the patients with right temporal dysrhythmia presented the lowest remission index.