This research presents a descriptive study on regarding the use of a research-based approach by teachers to clarify problems they encountered in multicultural classrooms. It analyses the outcomes of a training in which seven teachers from a Dutch Senior Secondary Vocational Education school participated conducting a research-based approach to explore the current practice of their multicultural classrooms. To determine the learning outcomes semi-structured interviews were conducted with the teachers with questions matching the domains of change in Clarke and Hollingsworth(2002) Interconnected Model of Teachers Professional Growth. Our main question was to what extent a research-based approach can help teachers to clarify the problems they encountered in their multicultural classrooms. According to the external domain of Clarke and Hollingsworth they become encouraged by sources of information from experts and literature. The teachers did not always have a positive attitude towards all research activities.