This study was designed to test the reliability and validity of an instrument to assess adolescent health status. Reliability and validity were examined by administration to adolescents (ages 11-17 years) in eight schools in two urban areas, one area in Appalachia, and one area in the rural South. Integrity of the domains and subdomains and construct validity were tested in all areas. Test/retest stability, criterion validity, and convergent and discriminant validity were tested in the two urban areas. Iterative testing has resulted in the final form of the CHIP-AE (Child Health and Illness Profile-Adolescent Edition) having 6 domains with 20 subdomains. The domains are Discomfort, Disorders, Satisfaction with Health, Achievement (of age-appropriate social roles), Risks, and Resilience. Tested aspects of reliability and validity have achieved acceptable levels for all retained subdomains. The CHIP-AE in its current form is suitable for assessing the health status of populations and subpopulations of adolescents. Evidence from test-retest stability analyses suggests that the CHIP-AE also can be used to assess changes occurring over time or in response to health services interventions targeted at groups of adolescents.