Abstract The link between gallstones formation and diabetes mellitus remains controversial. The study aims to find the prevalence of gallstones in diabetic patients and its relation with status of control, and duration of diabetes mellitus. A case-control study was conducted in Al-Basrah General Hospital; Basrah city, southern Iraq from January 2015 to September 2015. The study enrolled 100 type 2 diabetic patients with no abdominal pain (60% females, 40% males) as a test group and 100 asymptomatic subjects with no diabetes mellitus (60% females, 40% males) as a control group. Both groups were comparable for gender, age, and body mass index and examined by ultrasound to find gallstones. Blood samples were taken for fasting blood glucose and body mass index was measured. Age, gender, family history of gallstones, and parity for females were recorded in both groups. The tested group was further divided into two subgroups with and without gallstones. The association between duration of diabetes mellitus and hemoglobin A1c level with gallstones was assessed. Gallstones were detected in (28%) of diabetic group and (12%) of controls, which was highly statistically significant (p value=0.005). The prevalence of gallstones was found to be significantly higher among those with more than 10 years of diabetes and poor glycemic control compared with those with less than 5 years and good glycemic control. The study suggested that diabetic patients are at higher risk for gallstones in comparison to non-diabetic patients. Gallstones are found to be higher in those patients with long duration of diabetes mellitus and poor glycemic control.