This study evaluated which factors most influenced the impact of childhood asthma on the child's family. Seventy children/families seen at a tertiary-care hospital for asthma were evaluated. Stepwise multiple regression examined the effects of illness severity; family socioeconomic status (SES); family structure; social support; child's emotional characteristics; parent's health; family functioning; and maternal psychological distress on the Family Impact of Illness Scale. Analysis indicated that only the parent's Psychiatric Symptom Index significantly predicted impact scores. The most important predictors of how much impact a child's asthma has on the family are parental emotional distress and amount of social support.