This paper presents a new multi-scale instrument--the Bronstein-Cruz Child/Adolescent Self-Concept and Adjustment Scale, which measures self-concept and psychological adjustment for children and adolescents, aged 10-18 years. It consists of five subscales: Self-Evaluation, Social and Peer Relations, Family Relations, Sense of Mastery, and Emotional Well-Being/Distress, plus a total scale score as an indicator of overall positive self-concept and functioning. The instrument has been administered to approximately 1,000 children in grades 5-12, and norms are currently being established. Whole scale reliability (alpha) ranged from 0.93 to 0.95, and subscale reliabilities ranged from 0.69 to 0.90, with a mean of 0.84; these are higher than any published reliability coefficients for similar measures. In addition, other measures administered concurrently in an in-depth study of 43 fifth graders indicate good convergent and criterion validity for the instrument. Comparisons between this scale and other measures are summarized in chart form. (Author/SLD)