The aim of this study was to determine the professional developments of science teacher candidates over 14 weeks of microteaching practices. The sample for the study was comprised of 9 teacher candidates aged 21-23 who were studying their final year (4th year) in an elementary science education undergraduate programme of an education faculty in the western part of Turkey. The teaching practice course in which all the participants were enrolled is an 8-hour-required course. A 2-hour face to face theoretical part of this course is conducted at the university, and a 6-hour application part is conducted in a real school environment. In the study, nine preservice teachers taught three science topics at their practice schools, supported by the theoretical knowledge provided to them by academic staff. Data were collected using the "Teachers' Development Scale." It was assumed that the obtained data reflected the level of the professional development with respect to pedagogical, pedagogical content and content knowledge competences of the preservice teachers. Quantitative approaches were utilised in the data analysis. As a result, it was found that the competence scores of all the preservice teachers increased with the microteaching applications. Also, competence scores showed statistically significant differences over the practice sessions with respect to the academic achievement levels of the preservice teachers.