Illness-specific patterns of adjustment and cognitive adaptational process were identified in children (7-12 years of age) with cystic fibrosis (CF, n = 40) or sickle cell disease (SCD, n = 40). Anxiety diagnoses were most frequent for both illness subgroups but children with CF had a higher rate of oppositional disorder (27.5%) than did children with SCD (2.5%). Significant portions of the variance in adjustment were accounted for by stress appraisal (19%), expectations of efficacy (9%) and health locus of control (9%) for children with CF and by stress appraisal (21%) and self-worth (12%) for children with SCD. The interaction of general and specific illness tasks and adaptational process with developmental tasks in delineating intervention opportunities is discussed.