There is a need for adequate instruments to measure mental health in juvenile population. The objective is to obtain the reliability and factorial structure of the Child and Adolescent Assessment System (SENA) self-report versions of 8-12, and 12-18-year-olds in a sample of Chilean children and adolescents. The first was composed of 1921 students, and the second of 3077. A total of 49.4% were women and 50.6% men. The reliability of each of the scales was adequate. In most of the scales it was .75 or more, in both versions. The factorial structure, considering 14 of the primary scales and 20 of the secondary scales, obtained sufficient goodness of fit in both samples (chi(2)/gl<5, RMSEA<.05, SRMR<.08). The personal resource scales were left out of the models. Both versions of self-reporting SENA considered in the present study have acceptable psychometric properties.