Attendees at a holiday party hosted by Norris & Stevens, a property management company based in Portland, Oregon, on December 13, 2013 became ill with norovirus. Approximately 380 employees and guests attended the event. Forty three of the 76 people interviewed met the case definition. Consumption of 3 food items was statistically associated with illness: pork loin (RR=1.63, CI 1.1-2.43; p=0.0182), smoked salmon appetizers (RR=1.55, CI 1.04-2.31; p=0.035) and coffee (RR=1.57, CI 1.12-2.21; p=0.0457). Eight party attendees were laboratory confirmed with Norovirus GII.4 Sydney. One DoubleTree employee was also positive for Norovirus GII.4 Sydney. No one was hospitalized and no one died. Investigators were not able to determine the specific source of the outbreak. They noted that other groups served the same food items did not become ill and theorized that the spread of illness could have been via person-to-person of an attendee who was ill at the event.