This research was carried out to identify teachers’ professional competence development about inclusive practice and their advice for prospective teachers about this practice. Parallel Mixed-Methods Design was used in this study. In the quantitative research part of this study, ‘The Development of the Professional Competencies Scale’ about Inclusion for teachers was used. Also, In the qualitative research part a Semi-Structured Interview Form was used to learn the recommendations of teachers who work in inclusive practices to prospective teachers about these practices. In this research, for data analysis in quantitative research part; percentage, frequency and arithmetic mean took part in descriptive statistics were used. Regarding the qualitative part, content analysis was implemented. As a result of this study, it was found out that teachers' professional development competencies related to inclusion were moderate, teachers' professional development competencies for inclusion didn’t differ according to gender, teachers' getting education for inclusion was an important factor which determines teachers' professional development competencies for inclusion, and it has been determined that teachers' age, branches, the type of disability of their students are not important factors on their professional development competencies for inclusion. Teachers, about inclusion practices, teacher candidates; They provided advice on professional development, special education content information, arrangements for students, cooperation with staff, parent training, IEP training and integration adaptations.