To assess the relation between old age and mortality and morbidity in associated diseases, 789 patients older than 65 years who underwent operations for biliary lithiasis are presented in this study. It has been shown that, although mortality and morbidity are related to the age of the patient and to the presence of associated diseases, it is also affected by operative findings, such as dilation of the common bile duct, the incidence of bile infection, pathologic changes in the biliary tree and the type of supplementary procedure in instances of choledochotomy. It was possible to demonstrate that, irrespective of the clinical presentation, infected bile is associated with a higher mortality and morbidity than is sterile bile. Moreover, mortality and morbidity were higher after cholecystostomy-choledochotomy than after cholecystectomy only; it has been shown that there was a higher mortality and morbidity after t-tube drainage than after choledochoduodenostomy in patients who, after choledochotomy, underwent the foregoing supplementary procedures. The aforementioned features demonstrate that, in the presence of infected bile, associated with dilation of the common bile duct, due to advanced pathologic changes in the histology of the biliary tree, t-tube drainage has to be avoided. Indeed, in this series of patients, t-tube drainage failed to achieve adequate decompression of the biliary tree and initiated exogenous acquisition with environmental microorganisms which are associated with an increase in the mortality and morbidity.