The golden standard in clinical trial practice is to follow what it is pre-specified in the study protocol. However, there are situations where deviations from the protocol are occurred. For example, the investigator may develop new inclusion/exclusion criteria during the conduct of trial. It is difficult to maintain integrity on trial conduct when trial implementation deviates from the protocol. The type I error rate may not be controlled as planned and bias could be introduced. In this round table, we plan to discuss the impact of protocol deviations in the conduct of clinical trial.