[영문]This study reports the evaluation of an intervention designedto reinforcetobacco abstinence amongelementary schoolchildren in a school transition period. This intervention was developed according to the principles of Intervention Mapping. A total of 765 grade 5 students (ages 10-12) was recruited in 32 elementary schools. A quasi-experimental longitudinal design was used to evaluate the outcomes. Results observed 2 and 8 months postintervention are reported here. It is shown that although the behavior remained largely unchanged by the intervention, some of its determinants were modified. Behavioral intention, behavioral and normative beliefs, perceived self-efficacy, and role beliefs were changed at one or both postintervention measures. An interesting feature of these results relates to the fact that the most positive outcomes were seen among at-risk children. Discussion considers the advisability to develop, implement, and evaluate evidence-based interventions targeting the psychosocial factors underlying maintenance of tobacco smoking abstinence in elementary school.