OBJECTIVE Ramadan fasting creates changes in lifestyle, causing biochemical alterations that affect glucose metabolism and insulin sensitivity. This study aims to assess the impact of Ramadan fasting on glycemic control and Fetuin-A, a glycoprotein that affects insulin resistance, in patients with type 2 diabetes mellitus (T2DM). METHODS This was a prospective study done among 37 patients with T2DM from Internal Medicine Polyclinic in a hospital in Jakarta, Indonesia. Anthropometric data as well as Hemoglobin A1c (HbA1c), Fasting Blood Glucose (FBG), and Fetuin-A levels of the subjects were measured in three time points: before, during, and after Ramadan fasting. A bivariate analysis was done to see the effect of Ramadan fasting on those parameters. RESULTS Ramadan fasting reduced Fetuin-A levels [median (minimum-maximum), 5.35 (2.91-7.81) vs. 3.22 (2.35-5.60) mg/dl; p = 0.039] four weeks after the end of Ramadan compared to pre-Ramadan. After two weeks of Ramadan fasting, we found a significant reduction in body weight, BMI, FBG, and HbA1c levels which rebounded to baseline level after Ramadan. CONCLUSIONS Ramadan fasting was associated with a significant decrease in Fetuin-A level post Ramadan.