To make a proposal for the revision of KGCP, ICH Harmonized Tripartite Guideline for Good Clinical Practice, which is on the stage of worldwide implementation, was compared with current GCPs of tripartite countries of ICH, namely USA, Europe and Japan as well as Korea. On the basis of the classification in ICH GCP, comprehensive comparisons among the corresponding articles of 4 regions or countries were made in the order of IRB / IEC, Investigator, Sponsor and Clinical Trial Protocol. Based on the comparisons of the contents in ICH-GCP with those in current GCPs, major suggestions for the revision of current KGCP can be made as follows. Firstly, the function of IRB / IEC needs to be strengthened for the initiation and continuation of clinical trial. Current 2-step approval system of IRB / IEC and Health Authorities requires to be converted into the system similar to that of developed countries. Secondly, sponsor's obligation needs to be tightened to control and assure the quality of clinical trial. Inspection of regulatory authorities should be made to perform during and / or after clinical trial, when it is necessary. In other words, sponsor should be made to establish written Standard Operating Procedures (SOPs) for all aspects of clinical trial including monitoring to ensure that trials are conducted and data are generated, documented, and reported in compliance with the protocol, GCP, and the applicable regulatory requirement (s). Besides, the provision of ‘Quality Control and Quality Assurance’ should be added to the protocol to establish the credibility of the result of the clinical trial.