Clinical specimens as well as associated laboratory data (values and images) have been utilized to assure the overall quality of laboratory testing systems, including the evaluation of assay performance, individual analysis for the diagnosis and safety of patients, and education of medical laboratory technologists. Such secondary uses of clinical specimens and laboratory data require compliance with regulations and guidelines concerning ethical and social issues. We formulated an internal rule regarding the secondary use of specimens and laboratory data in our clinical laboratory, according to the view of the Japan Society of Laboratory Medicine (2002), and implemented it. Because a profound consideration of personal information and any conflict of interest has been recently emphasized in Japan, we have revised our internal rule. It is important to continue discussions on these ethical and social issues and observe the regulations and guidelines for the laboratory-based uses of post-assay specimens and data.