Investigated the relationship between maternal and child emotional adaptation both across and within samples of children with cystic fibrosis (CF) and insulin-dependent diabetes mellitus (IDDM). Higher levels of maternal depression were associated with increased depression in children with IDDM. In addition, increased illness severity and greater length of time since diagnosis were related to increased depression in children with IDDM. Whereas maternal depression was related to decreased trait anxiety for children in the CF group, neither maternal anxiety or depression were associated with child depression or state anxiety. Empirical and clinical implications of a disease-specific approach to studying chronic disease in children are discussed.