To evaluate the Brighton Collaboration case definition of acute intussusception, we reviewed all episodes reported to the Swiss Paediatric Surveillance Unit (SPSU) during 1 year (4/2003--3/2004). Of 96 confirmed episodes 86 (90%, 95% CI 83--96) were captured by the case definition. Of the remaining 10 episodes, 9 resolved spontaneously following presentation with clinical signs and symptoms, and ultrasound findings compatible with intussusception. Eighty-two episodes met level 1 of the definition, the highest level of diagnostic certainty. Compared to level 1, the sensitivity of level 2 (intermediate level) and level 3 (lowest level) was 65% (CI 55--74) and 30% (CI 20--40), respectively. In conclusion, the case definition was useful and applicable to assess the background rate of intussusception in the light of potential future rotavirus immunization.