Laboratory-based surveillance by OzFoodNet in Australia and FoodNet in the USA indicated that the incidence of
Campylobacterinfections in 2001 in Australia was about nine times higher than in the USA. We assessed whether this disparity could be explained by differences in the frequency of stool culturing. Using data from population surveys of diarrhoea and symptom profiles for Campylobacterfrom case-control studies, indices of healthcare behaviour taking into account the severity of Campylobacterinfections were calculated. These suggest that culture-confirmed Campylobacterinfections underestimate the incidence of community cases by similar ratios in the two countries. The incidence of Campylobacterinfections in Australia was about 12 times higher than in the USA after consideration of healthcare system differences.