741 cholecystektomies were examined for cholesterosis. In 92% gallstones were present and in 8% there were no stones. Cholesterosis of the gallbladder was found in 0,9% of 4417 autopsies. It was combined with gallstones in 25% and in 75% it was not. There was no difference concerning the clinical symptoms between cholesterosis with and without stones in the surgical patients. Cholesterosis without stone presented the same picture as gallstones. In the autopsy material however no typical symptoms could be found indicating either cholesterosis with gallstones or without. In the histological examination 80,5% of the cases with gallstones in the surgical and autopsy group had inflammatory changes of the gallbladder wall whereas only 22% of the cases with stoneless cholesterosis showed these alterations. Fibrosis of the gallbladder wall however was found in 86,1% in cases with cholesterosis without stones and in 88% in cases with stones. From these findings the conclusion is made that cholesterosis is no well defined disease. Clinical symptoms seem to appear only when other factors, such as stones, inflammation or functional disturbances probably because of fibrosis of the wall, become manifest in addition.