Epilepsy is among the most common findings associated with chromosome aberrations, particularly those involving autosomal chromosome imbalances. Most chromosome aberrations can be associated with different seizure types, but there are a few aberrations featuring specific seizure and electroencephalographic (EEG) patterns. The analysis of electro-clinical patterns associated with chromosomal aberrations is a major tool in the identification of epilepsy susceptibility genes. Advances in molecular cytogenetic techniques will certainly increase the diagnostic yield, and an increasing number of individuals previously diagnosed as having "cryptogenic" epilepsy will turn out to have an underlying chromosomal aberration. We review the types of seizures, EEG findings, and their natural history in the chromosomal disorders that are consistently associated with epilepsy.