The prevalence of gallstones and gallbladder disease was studied in a rural Caucasian population. All the women aged 15 to 50 years were asked to complete a questionnaire, undergo cholecystography and keep a food record for 4 consecutive days. The gallbladder status was assessed in 73%. The prevalence of gallstones in this population, 167/1000, was considerably higher than that reported in the Framingham study (59/1000) but was not significantly different from that recently found in Micmac Indian women living nearby in Canada (211/1000). In contrast to all the other studies in Caucasian women, this study showed the prevalence of gallstones to peak between the ages of 30 and 39 years. The risk factors, controlled for age, were found to be obesity, a narrow range of daily energy intake, a low daily calcium intake and limited activity. Discriminant analysis showed that skinfold thickness and range of daily energy intake or all measures of obesity together correctly separated the persons with gallstones from those without.