In July 2010, the U.S. government sponsored an interactive Marine Mammals and Sound Workshop with governmental and non-governmental stakeholders to solicit input on key issues related to (1) marine mammals and anthropogenic noise effects analysis and (2) monitoring and mitigation measures development. The meeting was organized and co-chaired by the Department of the Navy, National Oceanic and Atmospheric Administration, and Bureau of Ocean Energy Management and was sponsored by the U.S. Committee on Ocean Policy Joint Subcommittee on Ocean Science and Technology. Participants represented the marine mammal research community, including federal government, academic institutions, independent science corporations and organizations, non-governmental organizations, and industry, who had an existing understanding of anthropogenic sound and marine mammals and were active in research, policy development and other fields to address this issue. The agenda allowed for interactive discussions (rather than an emphasis on presentations) with most of the time spent in small discussion groups followed by plenary sessions. Discussions were conducted in four topical areas, including: (1) biologically significant effects of sound exposure (baseline data and assessment); (2) understanding and reducing sound generation and propagation; (3) acoustic behavioral harassment criteria and methodologies for cumulative effects analysis and mitigation; and (4) improving monitoring technology and methodologies.