Abstract : Critical environments of aviation such as hypoxia, decompression, low temperature, high speed and acceleration forces required the advent of aviation medicine. Aviation medicine started as aviation physiology and methodology of selection and training of the pilot. Aviation medicine and flight surgeon contributed to the pilot's health management and aviation safety. The territory of aviation medicine has expanded to accident investigation, humanfactor engineering of the cockpit, traveler's medicine, aeromedical transportation and space medicine, and so on. Problems of space medicine consist of various domains, such as cardio-vascular deconditioning, bone loss, muscle atrophy, cosmic radiation protection and psychological support. Research and resolution of these problems during the space flight contribute to the various fields of clinical medicine on the earth. Outlines of the aerospace medicine are presented in this paper.