Choline which is absorbed from the intestine isne produced no change in bile salt pool size or secretion rate. However, with each increment in dietary choline, biliary lecithin as well as cholesterol secretion rates were significantly increased. The results demonstrate that although bile salt is required for biliary lecithin secretion, the magnitude of secretion is principally dependent upon the extent of biliary lecithin synthesis, which in turn may be regulated by the amount of dietary choline. Results further indicate that biliary cholesterol secretion is more closely linked to lecithin than to bile salt secretion. These findings would therefore suggest that lecithin secretion might be independently manipulated when bile salt is deficient to achieve enhanced biliary cholesterol transport.