The main purpose of this study was to determine the opinions of the teacher candidates who attend thepedagogical formation certificate programme for the professional competency of instructors. Themethod of the research is a descriptive survey based on scanning. The study group included the teachercandidates who attend the pedagogical formation certificate programme organized in Cankiri KaratekinUniversity. In order to collect the data of the research, “Scale of Professional Competency of Instructors(OEMYO)” was developed. The professional competencies were classified into 5 main sections and ineach section, totally 50 behaviours are determined. For five sub-sections of OEMYO, validity study wasdone separately with factor analysis. The construct validity of each professional competency isdetermined by descriptive factor analysis. Research data were analysed by applying t-test, KruskalWallis-H test and Mann Whitney U test as well as descriptive statistics. In this research, it wasdetermined that the instructors constantly perform the professional competencies during study period.There was no significant difference in the views of teacher candidates related to developing professionalcompetence of instructors according to their education levels and when they graduated. On the otherhand, there were significant differences in certain professional competencies according to the gender ofthe teacher candidates and the departments they graduated from