The effects of childhood epilepsy on family interactional patterns were examined with eight families with a child with epilepsy and eight matched control Ss. Families were observed in their home environment using a coded, direct observation tool, the Family Observation Record Keyboard System (FORKS), and the portable electroencephalographic telemetry system which allowed trained observers to code all social and nonsocial behavior of all family members together with clinical and subclinical seizures. Families with an epileptic child were found to behave differently than do families with a nonepileptic child: the behavior of experimental families was less stable across observations. Significant correlations were obtained between seizure activity and the behavior of the identified child. (CL)