SERDP and ESTCP co-sponsored a workshop to define a path forward to further reduce the uncertainty surrounding dense nonaqueous phase liquid (DNAPL) sites by providing (1) a critical review of the progress to date, including a consensus perspective on the implications of the funded research for practical remediation; (2) an overview of the current state of the science; and (3) a summary and prioritization of the remaining data gaps.  More than 40 experts participated in the workshop, which defined key issues and critical and high-priority needs for both research and demonstration projects.  Results are described in the Workshop Final Report, which will guide the SERDP and ESTCP strategic plan for investments toward DNAPL source zones over the next 5 to 10 years.