The Department of Defense is responsible for the remediation of thousands of contaminated groundwater sites. SERDP and ESTCP have funded considerable research and technology demonstrations in the past, with an emphasis on chlorinated solvents, but also included several other contaminants of importance to DoD. However, the long term management of contaminated groundwater sites continues to pose technical and regulatory challenges, particularly for complex sites, such as source zones within fractured bedrock. SERDP and ESTCP convened a workshop to indentify research, development, and demonstration needs that would improve DoD’s ability to effectively address its environmental requirements to manage and reduce the impacts of contaminated sites. The focus of the workshop was on the research needed to more efficiently deal with the long-term management and lengthy restoration of complex sites. A review of the research, demonstration, and technology transfer needs identified is presented in the Workshop Report.