The results of a prospective study using ultrasound to assess abdominal complications in 76 children with proven cystic fibrosis are reported. Fifty-six patients (74%) had normal liver ultrasound scans. The most striking abnormality was an irregular, inferior edge to the liver occurring in 85% of abnormal liver scans and in 70% there was corresponding clinical and biochemical evidence of abnormal liver function. This finding has been only briefly mentioned before. Increased reflectivity in abnormalities of the pancreas and gallbladder is also described.