Electroclinical features of neonatal seizures were studied in 215 neonates who developed seizures during the first three weeks of life. In 62 of them, clinical fits occurred during the actual polygraphic recording. The electro-clinical correlations were very variable, although there were some statistically significant associations between certain types of seizures and electrical discharges. The relation between seizures and sleep states was investigated in 40 infants who had more than three fits during the recording. The state in which more than 70% of seizures occurred was active sleep in 28% of the cases, quiet sleep in 13%, indeterminate sleep in 8%, and wakefulness in 8%. In 50%, seizures did not tend to occur in a given state. The authors thank Professor Suzuki for his continued interest and encouragement.