This study focuses on the protection of trial subjects, who participate in clinical trials for new drug. It takes long time to develop new drugs and the clinical trials are required. Usually, pharmaceutical company, which develop new drug, request a research institution(usually, hospital) to investigate the examination of security and side effects of new drug. The institution recruit trial subject to participate in the trials. The contract for clinical research of investigational new drug is concluded between the pharmaceutical company and the institution. This thesis studies the legal regulations for protection of participants of clinical research for new drug. In this respect the first matter of this study is to seek which relation between pharmaceutical firm and participants of clinical trials. Especially, there is a question which the trial subject is entitled to demand the pharmaceutical company which requested clinical trials the institution to supply the investigational new drug, after the contract for clinical trials had terminated or cancelled. This study take into account the liability of the pharmaceutical company to trial subject. Secondly, it is researched the roles and authority of Institutional Review Board(IRB). IRB is Research Ethics Committee of the institution, in which clinical trials for new drug are conducted. According to the rule of Korea good clinical practice(KGCP), IRB is the mandatory organization which is authorized to approve, secure approval or disapprove the clinical trials for investigational new drug in the institution. The important roles are the review of ethical perspective of trial research and the protection of trial subject. Thirdly, this paper focuses if the participants are to be paid for the participation for clinical research. This is ethical aspect of clinical trials. It is resonable that the participant is reimbursed for expenditure such as travels, and other expenses incurred in participation in trials. It is not allowed that the benefit of clinical trials is paid to trial subject. The payment should not function as financial inducements for participations of trials. Finally, the voluntary consent of the trial subject is required. The institution ought to inform the subject, who would like to participate in trials, and it ought to received informed consent in writing for subject. In this regard, it is matter that trial subject has ability of consent. It is principle that the subject as severely psychogeriatric patient has not ability of consent. However, it is required that not only healthy people but also patients are allowed to take part in clinical trials of new drug, in order to confirm which the investigation new drug is secure. Therefore there are cases, in which the legal representative of subject consent the participation of the trials. In addition, it is very important that the regulations concerning clinical trials of new drug is to be systematically well-modified. The approach of legal and political approach is needed to achieve this purpose.