This is a longitudinal study of facial expression of affect in 28 children with intractable infantile spasms who underwent epilepsy surgery. After a mean follow-up period of 1.8 years, there was a significant increase in positive affect, a significant decrease in neutral affect, and no change in negative affect during a nonverbal communication paradigm. These findings were unrelated to surgical (i. e., side of surgery, type of surgery) or seizure-related variables (i.e., seizure control, age at onset of illness, duration of illness, change in antiepileptic drugs). Comparison of affect in a subgroup of 16 patients with those of 32 normal subjects suggest a normal age-related increase in the use of positive affect. Both before and after surgery, the patients used the most positive affect while not communicating. They also used significantly more positive affect during while requesting objects or assistance rather than during social referencing. Intractable infantile spasms might be associated with reduction in the facial expression of positive affect and with impaired use during social communication.