Intussusception is a major cause of intestinal obstruction in infancy and childhood. Improved results of treatment have followed the increased use of ultrasound imaging and pneumatic reduction. We prospectively studied the value of ultrasound in both the diagnosis and exclusion of intussusception in a peripheral paediatric unit over a four year period from October 1990 to October 1994. In all, 24 patients had a suspected clinical diagnosis of intussusception of which 19 had typical ultrasound findings. The male to female ratio was 8:11 and age at presentation ranged from 2 to 38 months (mean 11.4 months). There were no false negatives and 2 false positives giving a sensitivity to 100% and specificity of 89%. Thus no intussusception was missed by ultrasound examination. Enema reduction was successful in 76% of cases and factors associated with failure of enema reduction included passage of blood per rectum and symptoms for greater than 24 hours. We conclude that ultrasound should be used as a rapid and sensitive screening procedure in the diagnosis and exclusion.