The informed consent process (ICP) is still not enacted adequately despite its importance in clinical research. The researches on ICP have been mostly focused on the process to get a signature on the informed consent form and have not investigated ICP in a broad perspective. This article presented a novel classification of ICP closely related with the whole process of clinical research. ICP swere classified into 3 major stages, i.e. ICPs before, during and after the execution of clinical research. The first ICP before the execution of clinical research is composed of 3 detailed stages; 1) planning stage of clinical research, 2) preparatory stage of ICP, and 3) review stage of ICP. The second ICP, which is done during the execution of clinical research and a well-known ICP from the current narrow perspective, has 4 detailed stages; 1) notifying stage of clinical research, 2) providing stage of clinical research information, 3) deciding stage of clinical research participation, and 4) ICP stage during the execution of clinical research. The last ICP done after the execution of clinical research consists of 2 stages; 1) closing stage of clinical research, and 2) stage of sharing research results and final review. The activities, problems and ways to improve ICP in each detailed stage were further discussed.