BACKGROUND Historically, four divisions of the National Institute of Allergy and Infectious Diseases (NIAID) that manage clinical trials and oversee data and safety monitoring have operated fairly autonomously with respect to their approaches to Data and Safety Monitoring Board (DSMB) operations. We recognized the need for a revised policy on DSMB operations in an effort to encourage greater harmonization of procedures across the four divisions. OBJECTIVE The purpose of this article is to describe the considerations that motivated the development of the new policy, summarize current DSMB policies and ongoing harmonization efforts across the four divisions, and offer some recommendations for DSMB operations in the hope that other organizations may benefit from our experience. METHODS From 2005 to 2009, a working group undertook a review of DSMB responsibilities, policies, and operations. We analyzed and summarized the final policy document that the working group produced, gathered data describing current DSMB activities, and developed a tabular, cross-sectional overview highlighting how divisions are harmonizing their DSMB operations. RESULTS In 2010, there were 44 DSMBs in NIAID monitoring 169 protocols, and those DSMBs conducted 209 reviews of the protocols. Review and analysis of DSMB practices across the four divisions have led to recommendations for efficient and successful DSMB operations: adopt an inclusive approach, whereby the trial investigators assist in the process of forming and utilizing DSMBs; structures other than DSMBs can often provide many of the features of DSMBs but with greater flexibility in membership, access to interim data, and scheduling; the trial protocol should specify what safety and other concerns should trigger a DSMB review and what data should be included in prespecified reviews; present data in thoughtful and user-friendly ways that answer specific questions; allow sufficient time to plan for working with the DSMB. CONCLUSIONS We recognize that NIAID's specific circumstances and DSMB policy may not apply to the operation of DSMBs in every organization. Nevertheless, we believe that useful lessons can be learned from our experiences and efforts toward harmonization. CONCLUSIONS Homogeneity in DSMB operations and management has appeal as a matter of organizational policy and efficiency. Some limited flexibility, as long as it honors fundamental principles of independence, confidentiality of interim trial results, and clear lines of reporting and approval, may be appropriate on occasion. NIAID's 2009 institute-level policy established a collective understanding of the important contribution that DSMBs make to the responsible conduct of clinical trials. Thinking will continue to evolve, leading to further policy refinements and the continued assurance of patient safety in our clinical trials.