This quasi-experimental research is the subsequent part of the Health Promotion for Early Adolescents Project, which focuses on the training of schoolteachers in using the module Immune of Life for Teens, which was developed in 1999, for evaluating its impact. The module consists of a manual and a VDO cassette display of a story of a teenager who has difficulty adjusting to life changes. The program aimed at improving the coping skills and psychological health or mental health of junior high school students. Schoolteachers from 13 schools participated nationwide as part of an experimental group and received training in the use of the module in their schools with students in Grades 7-9. The control group was composed of 3 schools that did not apply the module. Each school performed the pretest and posttest 1 month after the module's application. The total number of the students in the study was 1,580. There were 445 students in the control group, 474 in the experimental I group (intensive training) group, and 661 in the experimental II group (nonintensive group). The instruments used to evaluate impact were the following: (1) Young Adult Coping Orientation for Problem Experiences, which was developed by Patterson, McCubbin, and Grochowski in 1983, and the (2) Thai Mental Health Questionnaire, a 70-item self-administered questionnaire developed by Pattrayuwat in 1999 to assess mental health status. The findings reveal that both experimental groups had better coping behaviors than the control group when using pretest scores as covariates (experimental I group: F = 9.425, p < .01; experimental II group: F = 22.446, p < .001) 1 month after the module was implemented. They also show that both experimental groups had better mental health than the control group when using pretest scores as covariates (experimental I group: F = 6.034, p < .05; experimental II group: F = 6.596, p < .001) 1 month after the module was implemented. The study confirmed the impact of the Immune of Life for Teens module on better coping behaviors and better mental health status among the subjects after it was implemented by their teachers. Thus, for further use of the module, intensive training for schoolteachers is recommended for the health promotion of early adolescents.