Through this book it is overviewed that reasons of turnover, turnover cost, components of comprehensive induction program, an example of comprehensive induction program, and various teacher learning theories and it is examined that the impacts of mentoring and induction activities on beginning teacher turnover using nationwide large data set of the School and Staffing Survey, 1999-2000 and the Teacher Follow-up Survey, 2000-2001 in the USA. To have more rigorous analysis, two restrictions are considered. First, turnver teachers are divided into four different subgroups. Second, various school characteristics and teacher characteristics are controlled. Through the analysis it is revealed that mentoring program showed positive influences on elementary beginning teachers'' turnover. Related to induction programs three induction activities are beneficial in significantly reducing turnover rates for beginning teachers: Seminars, common planning times, and extra classroom assistance.