In May 2013 a restaurant located in Bloomington, Minnesota was implicated in a norovirus outbreak. Approximately 28 people attended a conference held on May 7 and 8. Conference attendees ate breakfast and lunch at a restaurant in Bloomington both days of the conference. Attendees ate dinner on their own at different restaurants. City of Bloomington staff interviewed conference attendees about food and beverage consumption and illness history. Sixteen conference attendees were interviewed. Seven met the case definition. One case sought medical attention for their illness but was not hospitalized. In univariate analysis, no foods were statistically associated with illness, but consumption of white bread and swiss cheese served at the lunch sandwich buffet approached statistical significance. All restaurant employees were interviewed. One cook reported mild gastrointestinal illness on May 6. He went home that day and returned the next day. This employee plated the meat, cheeses, sliced tomatoes, and onions used for the sandwich buffet line on May 7. Bare-hand contact with ready-to-eat foods was not observed during this investigation but it had been noted and corrected during previous inspections. Two stool samples were submitted to the Minnesota Department of Health Public Health Laboratory by ill patrons and one by the mildly ill food worker. One patron's and the food worker's specimens were positive for norovirus GII.5, and the sequences were identical. Investigators concluded that this was a norovirus outbreak associated with eating one or more ready-to-eat foods from a restaurant during a conference. A food worker was the source of the outbreak.