A follow-up study has been made of 25 cases with infantile spasms, all of whom were six years old or more at review. Only four (16%) out of 25 cases made a full recovery and attended normal school. Spasms ceased in 96% of all cases, but fits other than spasms (grand mal, tonic seizure, atonic seizure, myoclonic seizure, atypical absence and psychomotor seizure) occurred subsequently in 11 cases (44%). The EEG became normal in two cases (8%), but still showed modified hypsarhythmia in three cases (12%), "epileptic non-hypsarhythmic" discharges in 17 cases (68%) and non-specific abnormalities in three cases (12%). The important factors associated with good prognosis were normal development before the onset of spasms, late onset (seven months old or over) and short duration of spasms, the absence of other types of fit following spasms and lack of neurological abnormality. A bad prognosis was associated with abnormal development prior to the onset of spasms, early onset and long duration of spasms, the presence of other types of fit following spasms and evidence of any neyrological abnormality This follow-up may confirm that the therapy with ACTH-A has no significant effect on final mental state.