The purpose of this study was to examine the professional development of teachers, their needs for the basis of knowledge, the relationship of their career to professional development and needs for the basis of knowledge and the relationship between their professional development and needs for the basis of knowledge. For the purpose, following research questions were set up. 1. How about the specialty development of the teacher, Is there a difference by a career? 2. How about the demand about the basics of knowledge, Is there a difference by a career? 3. How about the relations with the demand about the specialty development rank of the teacher and the basics of knowledge? The subjects in this study were 461 assistant principals and teachers in public kindergartens under the umbrella of the Gangwon-do Office of Education. An instrument used in this study to assess the professional development of the kindergarten teachers was Baek Eun-joo & Cho Boo-kyung(2004) s inventory, and the other used to evaluate their basis of knowledge was Cho Boo-kyung, Park Eun-hye & Lim Seung-ryeol (1998) s inventory. As to data handling, F-test was carried out to check their professional development and needs for the basis of knowledge, and Duncan test was utilized to make a post-hoc analysis. To look for connections between the level of their professional development and needs for the basis of knowledge, partial correlation coefficients were after having controlled a career. The research of this study were as followings: First, the professional development of the teachers was above the average in general. They scored highest in development of knowledge and knowhow, followed by ecological development and development of self-understanding. In regard to overall professional development by career, the teachers whose length of career was between 11 and 20 years ranked first, followed by those with 20 years or more of career, those with six to 10 years of career and those with five years or less of career. The intergroup gaps were significant. In terms of the three aspects of professional development, there were significant gaps in all the three aspects of professional development that involved development of knowledge and knowhow, development of self-understanding and ecological development. Second, they had strong needs for the basis of knowledge, which was above the average. They were most in need of understanding of children, followed by communication skills, research ability, understanding of the early childhood curriculum, understanding of kindergarten teacher professionalism, understanding of actual early childhood education, and understanding of educational and social phenomena. Concerning their overall needs for the basis of knowledge by career, the teachers whose length of career was between 11 and 20 years called for the basis of knowledge the most, but the gap between them and the others was not significant. As for the subfactors of needs for the basis of knowledge by career, career made a significant difference to their needs for understanding of educational and social phenomena, needs for under- standing of actual early childhood education and needs for research ability. Third, when the relationship between their professional development and needs for the basis of knowledge was investigated by keeping career in control, there was a positive correlation between the two(r=.42). The level of professional development had a positive correlation to the subfactors of needs for the basis of knowledge(r=.20 to r=.41). Among the subfactors of needs for the basis of knowledge, that was most closely linked to needs for research ability, followed by needs for understanding of kindergarten teacher professionalism, needs for communication skills and needs for understanding of the early childhood curriculum. Regarding the relationship between the three aspects of professional development and the subfactors of needs for the basis of knowledge, de