Can the Army effectively implement clinical treatment guidelines in its military treatment facilities to achieve consistent and high-quality practices throughout its health system? In partnership with the Army Medical Department (AMEDD), RAND has been working to implement clinical practice guidelines. This report evaluates the diabetes guideline demonstration. It documents the intended actions, assesses effects, and measures the quality and limitations of data for monitoring outcomes. The authors found that the implementation scored successes but resource limitations and organizational barriers curbed progress. They conclude that flexibility, adequate resources, and experience are the keys to implementing guidelines throughout AMEDD.