This article addresses the current theory, research, and implications of dietary fiber in the management of type 2 diabetes mellitus (DM; non-insulin-dependent DM). Dietary fiber shows promise in the management of type 2 DM. The inclusion of sufficient dietary fiber in a meal flattens the postprandial glycemic and insulinemic excursions and favorably influences plasma lipid levels in patients with type 2 DM. Water-soluble fiber appears to have a greater potential to reduce postprandial blood glucose, insulin, and serum lipid levels than insoluble fiber. Viscosity of the dietary fiber is important; the greater the viscosity, the greater the effect. Possible mechanisms for metabolic improvements with dietary fiber include delay of glucose absorption, increase in hepatic extraction of insulin, increased insulin sensitivity at the cellular level, and binding of bile acids. Patients with type 2 DM should increase their dietary fiber intake to 20 to 35 g/d and be aware of the considerations when increasing fiber intake. The nurse practitioner is in an ideal position to promote dietary fiber intake in such patients.