The present study aims at examining teacher’s professionalism and its reciprocal relation with functional position, rank stratification, length of work, and the diploma. Besides intended to verify the theory of James H. Stronge et al, this study can also be employed to evaluate Peraturan Pemerintah RI number 37 year 2009 Chapter 7, that states that teacher certification is valid as long as the teachers conduct their assignment as teachers, and it is not necessarily evaluated regularly. Data collection technique in the present study was executed through documentation and questionnaire. The  total of the student sample who provided their assessment on the teacher professionalism was 328, with 8 students representing each class. Each student provides their assessment for all teachers who were teaching in even semester of 2013-2014. Kendali tau was then employed for the data analysis technique. This study concluded that, firsly, functional position is negatively correlated with teacher professionalism at the Department of Tarbiyah STAIN Kediri; secondly, rank stratification is also negatively correlated with teacher professionalism; thirdly, length of teaching is not correlated with teacher professionalism; and fourthly, level of diploma is also not correlated with teacher professionalism at the Department of Tarbiyah STAIN Kediri.