Constipation and its complications, particularly meconium ileus equivalent, may become management problems in patients with cystic fibrosis. The medical records of 168 patients with cystic fibrosis were reviewed for the prevalence of constipation and meconium ileus equivalent. Of 168 patients, 54 (32%) had experienced at least one episode of constipation which responded to oral or rectal laxative therapy. In 16 of the study group (9%) meconium ileus equivalent developed. Patients younger than 5 years of age had a lower prevalence and those older than 30 years of age had a much higher prevalence of both conditions. Those with prolonged histories of inadequately controlled steatorrhea appeared to be at higher risk for the eventual development of meconium ileus equivalent. Recurrences and complications of constipation may be avoided by instituting early and aggressive therapy.