The aim of this work was to develop a simple model to evaluate the health care cost of diabetes in order to help decision-makers in selecting strategies for the prevention, control, and treatment of the disease. The model assesses the cost of full coverage of health care of diabetic patients free of chronic complications and in comparison with those of the treatment of acute and chronic complications. For that purpose, standardized cost figures were obtained from both annual control and treatment of uncomplicated diabetic patients and the treatment of one episode of ketoacidosis, acute myocardial infarction, and amputation of two toes. The treatment/prevention cost ratio obtained showed that prevention of a single episode of any of these late-complication-related events would provide enough funds to cover either the total or partial annual cost of control and treatment of several uncomplicated diabetic patients. These facts would favour the allocation of funds in such a way as to allow adequate control and treatment of diabetic patients to keep them free of the chronic complications of the disease. This would be a wise investment of funds, which would result in a reduction in the socioeconomic cost of the disease and in a better quality of life for the diabetic patients and their families.