Denny O. Day of VetPharm examines the role of clinical study monitor, the representative of the study sponsor and, as such, responsible for ensuring that the study is conducted in exact compliance with the protocol, that all study activities conform to good clinical practice (GCP) guidelines (VICH GL 9) and that all other regulatory requirements are met. If the study monitors have done their job well, there will be few, if any, surprises when the final study data is submitted to the sponsor or if one of their sites is audited by the regulatory agency.