The multi-disciplinary science panel for establishing an interim marbled murrelet underwater noise injury threshold was held on July 27–29, 2011, at the offices of the U.S. Fish and Wildlife Service (USFWS) in Lacey, WA. The panel was convened by the U.S. Navy and USFWS to develop recommended interim criteria for evaluating onset of injury to the marbled murrelet from underwater sounds resulting from pile driving. A description of the issues that led to this panel and preliminary questions for the panel’s consideration are included in Attachment 1 (Draft Issues/Questions for Multi-Disciplinary Panel for Marbled Murrelet Injury Threshold). The panelists represented technical experts and scientists affiliated with federal agencies, academia, and consulting firms who have expertise in underwater acoustics (including pile driving acoustics); sound impacts on fish, marine mammals, and terrestrial and marine birds; and the life history and demography of the marbled murrelet. This report summarizes the presentations, highlights of the discussions, and recommendations developed by panelists at this meeting. The intent is to document the technical reports and other information that were evaluated by the panel, demonstrate the range and depth of technical discussions, and provide the rationale developed in support of the panel’s recommendations. Outstanding issues related to data availability and potential refinements to the recommended interim criteria are also summarized. An overall summary of conclusions is presented at the end of the report. Additionally, references cited and attachments are included.