As in cystic fibrosis (CF), gallbladder (GB) hypokinesia might play a role in the high incidence of either cholelithiasis or atrophic and hypoplastic GBs. We studied the contractility of the GB by ultrasonography (US) in 57 CF patients and in 25 age- and sex-matched healthy controls. We evaluated the status of the GB, the GB volume after an overnight fasting and 30 min after the ingestion of a standardized milk meal, the GB contractility (the percentage of reduction, (%R) of the GB volume after a meal), the presence of gallstones, and finally, the span of the liver. In addition, liver function test results were evaluated in the CF group. We concluded that the mean values of GB contractility in CF patients do not differ from those of healthy controls, the most hypokinetic GBs (%R less than 40%) being observed, however, only in the CF group. Gallstones occur in CF patients with a greater frequency than seen in the normal population, even in early childhood. The CF patients' GB mean volumes in fasting conditions are significantly greater than in healthy controls (13.5 +/- 2 versus 8.5 +/- 1.5 cc, p less than 0.0001).