People who attended a birthday party at a bowling alley in Albany, Minnesota reported gastrointestinal illness after the November 24 event. Fourteen party attendees were interviewed. Eleven met the case definition. Stool specimens were collected from two party attendees and one employee at the bowling alley. All three were positive for norovirus GI. The Minnesota Department of Health Public Health Laboratory conducted sequencing from all three specimens. The sequences were identical. A variety of foods from several sources were served at the party. Stearns County Environmental Health (SCEH) sanitarians inspected the restaurant that prepared sandwiches and pizza. Food workers did not wear gloves but were observed washing hands frequently. There was no log of employee illnesses. No other reports of illness were linked to food prepared at the restaurant. SCEH obtained illness history and job duty information from all 22 bowling alley employees. No employee reported illness prior to the birthday party. Two employees reported gastrointestinal illness after the event. An employee who worked in the kitchen, bar tending, and managerial duties submitted a stool sample with was positive for norovirus. Public health investigators concluded this was an outbreak of norovirus associated with a birthday party held at a bowling alley. The vehicle of transmission and the original source of contamination were not identified. The most plausible scenario was that cooked pizza and/or ice were contaminated by an unidentifiable ill food worker. However, it is also possible that environmental surfaces were contaminated by an ill patron or employee.