Cystic fibrosis (CF) is the most common lethal genetic disease among Caucasian 
populations. The generally accepted incidence of CF in the United States is 1 in 
3,200 in the Caucasian population. Intestinal obstructions and atresias have 
been described among patients with CF. An association of CF with infantile 
hypertrophic pyloric stenosis (IHPS) has not been previously documented. A 
review in our clinic of 72 patients with CF revealed IHPS in two. The incidence 
of 2.7% is greater than the 0.3% incidence expected in the general population. 
This ninefold increase in IHPS in patients with CF suggests an association 
between the two and warrants further investigation.