All electroencephalograms performed in our institution between 1980 and 1990 were reviewed. The clinical characteristics of children with epilepsy and generalized spike-and-wave (SW) patterns were analyzed. The SW patterns were classified according to their frequency. Electroencephalograms of 154 children with epilepsy revealed SW patterns. Absence seizures were the most common first seizure, but partial seizures were frequent. More than 40% had several types of seizures. Sixty percent of the epileptic syndromes were generalized, but almost 25% were partial. The typical SW pattern was associated with absence seizures, a normal examination and computed tomographic scan, idiopathic generalized epilepsies, monotherapy, freedom from seizures, and lack of recurrence. The slow SW pattern was associated with West syndrome; a younger age at seizure onset; atonic, myoclonic, tonic, and partial simple seizures; an abnormal examination and computed tomographic scan; cryptogenic or symptomatic generalized epilepsy or symptomatic partial epilepsy; polytherapy; and poor seizure control. The fast SW pattern was associated with secondary generalized, partial, tonic-clonic, and complex partial seizures; a normal computed tomographic scan; cryptogenic partial epilepsy; isolated seizures; and seizure recurrence. Epilepsy with a typical SW pattern should be considered benign, epilepsy with a slow SW pattern malignant, and epilepsy with a fast SW pattern treacherous.