SummaryA review of priblished cascs of infantile spasms and hypsarhythmia treated u i t h ACTH and corticosteroids has been made and combined with preliminary data from a Swedish cooperative study. Pour hundred and seventy cases have been analyzed. The effect of treatment on the incidence of seizures, thc EEG and psychomotor development has been compared in different groups. Cases of unknown etiology and cases which are treated shortly after the onset of seizures show better results. The incidence of early recurrences lias been estimated. Thc more favourable results concerning psychomotor development iii the groups studied may be of great importance, but final evaluation must await morc thorough longitudinal studies With better psychometric methods and longer follow‐up.