There is a clear need for standardized measures to assess health status that are valid and appropriate to the needs of children with orthopaedic problems. The Child Health Questionnaire and the American Academy of Orthopaedic Surgeons Pediatric Outcomes Data Collection Instrument, two new pediatric health status measures, were assessed for their ability to detect differences in health states in a pediatric orthopaedic population. The instruments have a range of scales designed to measure various aspects of physical and psychosocial health. Two hundred forty-two patients with wide-ranging diagnoses were enrolled in this cross-sectional study. The instruments exhibited ceiling effects in some domains but generally performed as they were intended in this large cohort. Using secondary factor analysis, it was shown that the domains of the instruments appropriately distinguish physical and psychosocial health. Several domains from each instrument discriminated between diagnosis groups and patients with varying numbers of comorbidities. Both of these measures show significant promise and have an important role in helping define the outcomes of children with orthopaedic problems.