An outbreak of Campylobacter enteritis among staff on a resort island in north Queensland is reported. Untreated rainwater and food from the staff dining room were initially suspected as possible sources of infection but Campylobacter species were not isolated from any environmental samples. Faecal contamination was detected in four rainwater tanks. A case control study involved a total of 23 cases (7 confirmed and 16 probable), 3 of whom required hospitalisation. There was a strong association between gastrointestinal illness and consumption of water from a dispenser in the staff restaurant that had probably been filled from one of the contaminated tanks. We conclude that this was probably a waterborne outbreak and postulate that Campylobacter species were introduced into one or more of the tanks by contamination with the faeces of wild animals.