OBJECTIVES: To study the cost related to the management of type 2 diabetes mellitus (T2DM) in public health care by standard approach as a means to assist in the evaluation of health services in Brazil.  METHODS: A small municipality was considered for this study, with less than 50,000 habitants, it is representative of 81% of the state’s municipalities and 89% of Brazil’s. The data sources used were obtained from the Municipal Health Office and public data systems online. Direct medical costs were selected according to standard care recommended by the Ministry of Health and Brazilian Associations of Cardiology and Diabetes, and lately divided into three categories of analysis: Health professional salary, Procedures and tests costs, and Medication costs, both for Primary Health Care (PHC) and Medium/High Complexity Care (MHCC).  RESULTS: In 2011, the total expense in a year for a user with T2DM was U$ 491.04, regarding the individual without complication, attended in PHC. After developing chronic complications (either microvascular or macrovascular), the patient continues to receive PHC, but also needs the attention of specialists, therefore costs for specific treatments in MHCC services were added to the PHC costs. The sum ranged from U$ 732.86 for nephropathy to U$ 3182.59 for Acute Myocardial Infarction. In evaluation of each category of analysis, the investment made by the National Health System in the management of T2DM showed uneven distribution, where a subcategory of Health professionals salary, the PHC’s doctors salary, represented an important share of spending in exchange of others categories.  CONCLUSIONS: The standard cost method is presented as an alternative that offers greater convenience and flexibility in the determination of costs to assist health managers in decision-making, considering the shortcomings of Brazilian’s information system.