OBJECTIVE: To investigate the psychological development such as emotional and social aspects of typically developing siblings of children with cerebral palsy. METHOD: Eighteen siblings of children with cerebral palsy aged 5 to 12 years and their mothers were included and the interview and psychological assessment were administered by developmental psychologist. All children were asked to complete the Children's Depression Inventory (CDI), State- Trait Anxiety Inventory (STAI), Piers-Harris Children's Self- Concept Scale, Korea Child Behavior Checklist and Korean Educational Developmental Institute-Wechsler Intelligence Scale for Children (KEDI-WISC). All participating mother were asked to complete Minnesota Multiphasic Personality Inventory (MMPI), Beck's Depression Inventory (BDI). For control group, eighteen children with healthy sibling and their mothers were enrolled. RESULTS: Siblings of children with cerebral palsy showed higher mean score of CDI and STAI. And there were no differences in the CDI and STAI according to frequency of treatment, duration of treatment of children with cerebral palsy. There were no significant difference in Piers-Harris children's Self-Concept Scale and Korea Child Behavior Checklist between study group and control group. More than half of mothers of children with cerebral palsy showed depression in BDI and higher score of psychopathic Deviate and psychasthenia in MMPI. Children of mothers with depression in BDI showed higher mean score of CDI and STAI. CONCLUSION: It is necessary to consider extended service to promote psychosocial well-being of children with cerebral palsy and siblings in community-based service organizations.