The study objective was to compare the Taylor-Johnson Temperament Analysis secondary population norms for adolescents, to test results of Assemblies of God missionary adolescents, and determine if the mission's experience had significant impact on personality traits. A retrospective record review study of Taylor-Johnson Temperament Analysis test results administered to all missionary adolescents aged 13- to 18-years-old, having attended a yearly school of missions from 1986 to 1994, was performed. A two-sample, two-tailed t-test was used for statistical analysis. Test results were compared with standard adolescent and adult norms. Initial, and second test results when available, were compared for significant personality trait changes in adolescents over a 2-3 year interval, while in the mission's program. Subpopulation norms were calculated for the study group. Initial tests from 438 study group adolescents demonstrated significant differences in 7 of 9 personality trait categories for males, and 8 of 9 for females, compared with test adolescent norms. Initial, and second test comparisons were performed in 67 adolescents, and showed no significant changes in the personality trait scores in males and females. Personality trait profiles for females more closely resembled adult than adolescent norms, with 8 of the 9 personality trait categories showing no significant difference between adult female norms and study females. Clinicians and mission's sending agencies should be aware of the unique Taylor-Johnson Temperament Analysis test patterns for missionary adolescents, and that Taylor-Johnson Temperament Analysis norm tables for adolescents seem inadequate in evaluating missionary adolescents. Appropriate subpopulation norms are likely necessary. The impact of missions on personality trait categories of missionary adolescents seems negligible, but needs further research with methods that assure follow-up testing. These considerations could apply to other subpopulations and psychological tests.