Two newborn girls presented with congenital small-bowel atresia; in one case a high intestinal obstruction had been demonstrated by prenatal echography, while in the other case there were feeding problems and a failure to produce meconium. In both infants, the postoperative period was complicated by feeding problems, malabsorption and insufficient growth. Cystic fibrosis (CF) was then diagnosed in both patients. After modification of the diet, both showed rapid growth to a normal weight. The prevalence of CF in children with congenital small-bowel atresia is 6-13%, which is considerably higher than in a normal population. There is still no good explanation for this finding, but it is likely that CF contributes to the development of small-bowel atresia. In view of the high prevalence of CF in children with small-bowel atresia, children with congenital small-bowel atresia should be examined for CF.