An outbreak of Cyclosporiasis occurred among people who attended a fundraiser for the Big Sisters' organization in Sarnia, Ontario, Canada. All who became ill had eaten the Cool Pesto Crunch, an appetizer that contained fresh basil. The appetizer was provided to the event by Boston Not Chicago Catering Co. On two other separate occasions, others became ill after eating the appetizer. No food handling issues were observed on inspection of the catering facility. As of June 23, no food ingredient was confirmed as the cause of the outbreak, but previous outbreaks of cyclospora have been attributed to eating fresh basil. A traceback of the ingredients was initiated.