Increased spontaneous fluctuations in skin conductance (SC) in adult schizophrenics have been associated with high expressed emotion (EE) in their relatives. This is the first study in children where parental EE, parental psychopathology, and autonomic activity, indexed by SC levels and reactivity, have been assessed. The subjects were children and adolescents with disruptive behaviour disorders (DBD, n = 35), a psychiatric contrast group with obsessive–compulsive disorders (OCD, n = 42) and normal controls (NC, n = 45). Children living in homes with two high-EE parents had higher SC activity during rest period and slower adaptation to relaxation. Fathers' EE and maternal psychiatric diagnosis were related to higher SC activity, especially for the OCD group.