A new measure, the Strengths Assessment Inventory-Youth self-report (SAI-Y), was recently developed to assess the strengths of children and adolescents between the ages of 10 and 18 years. The SAI-Y differs from similar measures in that it provides a comprehensive assessment of strengths that are intrinsic to the individual as well as strengths associated with an individual's interaction with his or her environment. Based on over 10 years of test development as well as previous research, the 120 items of the SAI-Y contribute to 11 content scales (e.g., Strengths at Home) and 12 empirical scales (e.g., Commitment to Family Values). The purpose of the current report is to describe the procedure that guided the development of the SAI-Y coupled with an initial study of the psychometric properties of the instrument. The SAI-Y was administered to 572 elementary and secondary school students of which 455 also completed the measure following a one- to two-week interval. Based on this data, the following psychometric properties were examined: internal consistency, standard error of measurement, and test-retest reliability. Overall, results indicated that the SAI-Y demonstrates acceptable to good levels of reliability and may be a valuable addition to current measures that assess aspects of positive functioning. Ongoing research projects and future directions are discussed.