To assess the diagnostic value of ultrasound (US) in clinically suspected acute intestinal intussusception in children, the authors prospectively compared US and enema studies in 83 episodes. None of the cases negative at US proved to be intussusception at enema study (negative predictive value = 100%). The sensitivity of US was 100%, and the specificity was 88%. Most of the sonograms were initially obtained and examined by residents. Several unsuspected abnormalities were also found with US. The authors conclude that a few months of training in US appears to be sufficient for high-accuracy investigation of clinically suspected intussusception, enabling selection of those patients in need of an enema.