Regenerative medicine is regarded as innovative therapy for severe diseases and damages caused by tissue loss and functional impairment. In Japan, regenerative medicine is one of the most important subjects issued by Council for Science and Technology Policy and also referred to in Medical Innovation of New Growth Strategy. Cell/tissue-processed products are living cells, which have been manipulated or processed for the purpose of regenerative medicine, and are extensively developing. Human somatic cells, somatic stem cells, embryonic stem cells, and induced pluripotent stem cells are cell sources used for regenerative medicine. Since we lack in experiences with cell/tissue-processed products, technical development of safety and quality assessment is urgently needed. National Institute of Health Sciences has carried out a mission of Regulatory Science and worked on safety assessment of pharmaceuticals and medical devices and their guideline development. The objective of our study is to develop safety and quality assessment methods for cell/tissue-processed products derived from stem cells, based on recent progresses in life science. We are currently developing methods to evaluate products as follows; a) useful and quantitative tumorigenicity tests to detect contamination of undifferentiated and/or abnormal cells in products, b) quality assessment by gene expression analysis and detection of genetic stability in a manufacturing process, and c) analysis of quality attributes associated with propensity of undifferentiated cells to set acceptable criteria of cell banks. We will be able to provide indicators to control the quality, efficacy and safety of stem cell-processed products and support efficient and economical promotion of the products. Especially, this study would help translate stem cell science into therapeutic products to patients with severe and life-threatening diseases, consequently contributing to administrative policy of Ministry of Health, Labor and Welfare.