Hypothesized that maternal perceptions would be more significant predictors of emotional adjustment than medical severity. Mothers of 99 children, between the ages 4-10 years, completed the Child Behavior Checklist, Parenting Stress Index, Parental Locus of Control Scale, and a measure of perception of medical severity. Assessed medical severity by number of hospitalizations, operations, catheterizations, hospital days, outpatient visits, and a cardiologist's rating of illness severity. Maternal perceptions were potent predictors of emotional adjustment. Approximately 33% of the variability in adjustment was accounted for by maternal perceptions, while the medical severity accounted for less than 3% of the variability. Severity of illness appears less critical to successful adaptation than the quality of the mother-child relationship.