The natural history of gallstone disease in 691 patients, followed for a mean +/- SD duration of 78 +/- 61.6 months (median 62.9 months), is presented. These patients are all subscribers of a large health maintenance organization and are believed to represent a cross-section of middle income Americans. Symptoms attributed to biliary tract disease were present in 556 (80.5%), and the other 135 (19.5%) patients were asymptomatic. In the symptomatic group, the mean +/- SD duration of observation was 82.9 +/- 63.2 months (median 68.5 months); 242 (44%) eventually underwent biliary tract operations most often because of persistent symptoms. Only 10% of asymptomatic patients followed for 58 +/- 50.2 months (median 46.3 months) developed symptoms of biliary calculi, and seven per cent required operations. There were 50 deaths in this series of 691 patients, 25 in the symptomatic group, and 25 in the asymptomatic. Only two of these deaths were biliary tract related, and both were in the symptomatic group. This study suggests that patients with silent stones do not need to be operated on prior to the development of symptoms. In addition, many patients with symptoms of biliary calculi can tolerate their symptoms for long periods of time and prefer this course of action to cholecystectomy.