A review of the gall-bladder content of the 193 patients that underwent a cholecystectomy at the University Hospital of Lausanne, Switzerland, in 1977, was done in order to find out the diagnostic accuracy of sonographic examination of the gall-bladder, oral cholecystography and intravenous cholangiography. Sonographic examination of the gall-bladder proofed to be accurate in 92.5% of 109 cases. We found a false negative rate of 4.5% (5 cases) and a false positive rate of 1% (1 case) as well as an indeterminate rate of 2% (2 cases). In 37% (46 cases) of the 124 patients that underwent oral cholecystography and/or intravenous cholangiography the gall-bladder was not visualized. Sonographic examination of gall-bladder is free of side effects and can be done on emergency, on jaundiced or pregnant patients, and it is enough reliable for the surgeon to make a decision to operate the gall-bladder. Low cost of the procedure is another point in favour of sonographic examination of the gall-bladder.