Cholesterol gallstone is known to occur two to three times more frequently in diabetes than in normal population. Hypotheses such as hypercholesterolemia or obesity were presented to explain the higher incidence of gallstone disease in diabetes but failed to show strong cause-effect relationship. We compared the gallbladder emptying of a diabetic group who had not ever had gallstone disease with that of a control group using Tc-99m cholescintigraphy and also made assessment about several metabolic factors in diabetic group to know which one was closely related with the impaired gallbladder emptying. The results are as follows. 1) Gallbladder emptying (ejection fraction) was significantly reduced in diabetes group (72.9 +- 19.8%) compared with normal control (89.6 +-9.6%) (p<0.05). 2) Gallbladder emptying in the diabetes group with autonomic neuropathy (64.2 +- 21.6%) was impaired to a greater extent than in the diabetes without autonomic neuropathy (82.3 +- 12.3%) (p< 0.05). 3) Severe impairment of gallbladder emptying (EF < 70%) in diabetes was not related with obesity, Hb A,C level, disease duration or serum lipid level but related with the presence of autonomic neuropathy (p<0.01). In conclusion, gallbladder emptying is impaired in diabetes and such an impairment was more prominent in the diabetic patient complicated autonomic neuropathy, which may lead to bile stasis and allow for cholesterol crystal formation.