Abstract: Background and Objective: Dietary fibers have been identified to have beneficial effects in improving insulin secretion and insulin resistance. This study aimed to evaluate the effects of fiber-rich snacks on insulin secretion and insulin resistance in patients with type 2 diabetes mellitus (T2DM). Materials and Methods: Twenty patients with T2DM, ages 40-60 years were recruited from the Polyclinic of Endocrine, General Hospital Dr. Sardjito, Yogyakarta, Indonesia. The subjects received daily 32 g snacks made from a mixture of Dioscorea esculenta, arrowroot, cassava and pumpkin, for 4 weeks. Fasting plasma glucose, insulin and C-peptide levels were measured before and after intervention. Paired t-tests were used to evaluate the results. Results: Intervention of fiber-rich snacks for 4 weeks for T2DM patients significantly (p = 0.01) reduced fasting plasma glucose from 9.3±2.7 to 8.3±2.5 mmol L–1 and homeostatic model assessment of insulin resistance (p = 0.04) from 4.1±1.3 to 3.6±1.9 and significantly (p<0.001) increased C-peptide levels from 0.417±0.004 to 0.512±0.008 ng mL–1. Conclusion: In this study, fiber-rich snacks provide significant benefits to increase endogenous insulin secretion and reduce insulin resistance in patients with T2DM.