Observable practices of mathematics teaching in the period of the year 2001-2003 also indicated that many teachers still have difficulty in elaborating the syllabus; a number of mathematics topics are considered to be difficult for teachers to teach; a significant number of children consider some mathematics topics as difficult to understand; teachers consider that they still need guidelines for conducting teaching process by using science process skills approach. Results of the initiated Lesson Studies significantly indicated that there are improvements of the practice of secondary mathematics teaching learning processes in term of teaching methodology, teacher competencies, students achievements, alternative evaluation, teaching learning resources and syllabus. However, in term of the longer term for teacher development program, the result of initiated Lesson Studies can be perceived as merely a starting point. There are still many things to be done in order that mathematics teachers develop their professional development.