PURPOSE: The thickening of the gallbladder wall is a valuable finding for the diagnosis of cholecystitis, butmay be seen in non-cholecystic disease as well as in acute or chronic cholecystitis. The purpose of this study isto determine the value of color Doppler sonography in differentiating the causes of thickened gallbladder wall. MATERIALS AND METHODS: Ninety eight patients with thickened gallbladder wall(more than 3mm) which was not due to gallbladder cancer were prospectively evaluated with color Doppler sonography. Sixty-six cases, confirmed bypathologic reports and clinical records, were analyzed for correlation between thickened gallbladder wall andcolor flow signal according to the underlying causes. RESULTS: Of the 66 patients, 28 cases were cholecystitisand 38 cases had non-cholecystic causes such as liver cirrhosis, ascites, hepatitis, pancreatitis, renal failure,and hypoalbuminemia. Of the 28 patients with cholecystitis(12 acute, 16 chronic), 23(82%) had color Doppler flowsignals in the thickened gallbladder wall. Of the 38 patients with non-cholecystic causes, eight(21%) had color Doppler flow signals. There was a statistically significant difference of color Doppler flow signals between the cholecystitis and non-cholecystic groups(p=0.0001). No significant difference of color Doppler flow signals was found between cases of acute and chronic cholecystitis. Of the 23 patients with color Doppler flow signals in 28cases of cholecystitis, 18(78.3%) showed a linear pattern and five(21.7%) showed a spotty pattern. Of the eight patients with color Doppler flow signals in the 38 non-cholecystic cases, four(50%) showed a linear pattern andfour(50%) showed a spotty pattern. In cholecystitis, a linear color Doppler flow signal pattern is a much more frequent finding than a spotty pattern. CONCLUSION: Color Doppler sonography is a useful and adequate method for determining whether a thickened gallbladder wall is the result of cholecystitis or has non-cholecystic causes.