The purpose of this study is to clarify the characters of outcomes and assessments of teacher preparation programs in the United States through the analysis of some cases. In Japan, the accreditation system of teacher education is one of the critical educational issues in response to the introduction of professional school of education. In terms of the quality assurance of teacher preparation programs, the approval system of programs has played an important role since 1950s. The differences between accreditation and approval system are the subject, the ways, and so on. Also the focus of evaluation is different. Accreditation focuses on outcomes while approval system focuses on input such as the number of faculties. Therefore Japanese teacher preparation programs have little experiences of showing their outcomes. Meanwhile America has a long history of accreditation of teacher preparation programs. Then the starting point of focusing on the outcomes of teacher preparation programs in accreditation appeared from 1970s. And now outcomes are the most important factor in the decision of accreditation so that a lot of teacher preparation programs are going to deal with outcomes and develop new ways of assessments. Considering these situations, this study analyzes some American's case of outcomes and clarifies their characters in order to find suggestions for the outcomes issues of teacher preparation programs in Japan.