As clinical trials have emerged as the major research method for evaluating new interventions, the process for monitoring intervention safety and benefit has also evolved. The Data Monitoring Committee (DMC) has become the standard approach to implement this responsibility for many Phase III trials. Recent draft guidelines on the operation of DMCs by the Food and Drug Administration (FDA) have raised issues that need further clarification or discussion, especially for industry sponsored trials. These include, the time when DMCs are needed, the role of the independent statistician to support the DMC, and sponsor participation at DMC meetings. This paper provides an overview of these issues, based on the discussions at the January, 2003 workshop sponsored by Duke Clinical Research Institute. © 2004, SAGE Publications. All rights reserved.