The improving prognosis for pediatric leukemia patients requires that involved professionals increase attention to the emotional adjustment of these children. This study was designed to determine (a) how mothers of leukemia patients perceived their children's personalities in order to identify any specific emotional difficulties which these children may experience and (b) if their perceptions differed from either mothers of cystic fibrosis and diabetes patients or mothers of healthy children. Subjects included 24 mothers in each of three groups: leukemia, other illness, and healthy. Children in both illness groups received higher scores than healthy children on Adjustment, Achievement, Somatic Concern, Depression, Psychosis, and Social Skills scales as measured by the Personality Inventory for Children; however, only the leukemic children were rated higher in areas of Anxiety and Withdrawal. Implications for treatment and future research are discussed.