In Japan recently there arose a sudden need for special guidelines concerning medicolegal autopsy and the handling of medicolegal materials. In this respect, the Medico-legal Society of Japan, Committee on Expert Opinions has produced a guideline, entitled "Recommendations for Preventing Transmission of Infection with Biohazard in the Practice of Legal Medicine", which was then introduced to all members in Legal Medicine. This guideline contains First: Explanations about the most important types of Biohazard diseases, the dangers and ways of transmission. Second: Explanations concerning preventive measures in medicolegal autopsy, for handling of medicolegal materials and investigation samples, also concerning the equipment and tools within the autopsy room, as well as measures for correct disinfection. These guidelines, form the base on each department of the Medico-Legal Society of Japan, are asked to adjust their own practical manual in order to improve the safety of autopsy conditions.