Non-insulin-dependent diabetes mellitus (NIDDM) is considered to predispose impaired gallbladder function and an increased prevalence of gallbladder disease. The aim of this study was to evaluate the gallbladder function of patients with NIDDM by quantitative technetium-99m-labeled imino-diacetic acid analogue (Tc-99m DISIDA) cholescintigraphy. One hundred and forty-five NIDDM patients (100 males, 45 females; age: 58.7+/-9.5 years) with the absence of autonomic or peripheral neuropathy and without gallbladder or liver disorders were enrolled in this study. The patients were categorized by blood sugar control (HbA(1c)> or =10% as a poor blood sugar control group and HbA(1c)<10% as a good blood sugar control group) and disease duration (diabetic duration > or =10 years as a longer-duration group and diabetic duration <10 years as a shorter-duration group). In addition, 60 normal controls (38 males, 22 females; age: 59.1+/-10.2 years) were also studied for comparison. All NIDDM patients and normal controls underwent Tc-99m DISIDA cholescintigraphy, and the filling fraction (FF) and ejection fraction (EF) of gallbladder were calculated. The results showed significant difference between (1) NIDDM patients versus normal controls in FF and EF, (2) poor versus good blood sugar control of NIDDM patients in FF and EF, and (3) longer versus shorter disease duration of NIDDM patients in FF and EF. Our study, including a large number of subjects, showed that gallbladder function of patients with NIDDM is more impaired than the normal controls; and impaired gallbladder function in NIDDM patients is related to disease duration and blood sugar control.