Diabetes represents a high epidemiological and economic burden worldwide. The cost of diabetes care increases slowly during early years, but it accelerates once chronic complications set in. There is evidence that adequate control may delay the onset of complications. Management of diabetes falls almost exclusively into primary care services until chronic complications appear. Therefore, primary care is strategic for reducing the expedited growth of costs. The objective of this study was to identify predictors of primary care costs in patients without complications in the years following diabetes diagnosis. Direct medical costs for primary care were determined from the perspective of public health services provider. Information was obtained from medical records of 764 patients. Microcosting and average cost techniques were combined. A generalized linear regression model was developed including characteristics of patients and facilities. Primary health care costs for different patient profiles were estimated. The mean annual primary care cost was USD$465.1. Gender was the most important predictor followed by weight status, insulin use, respiratoty infections, glycemic control and dyslipidemia. A gap in costs was observed between genders; women make greater use of resources (42.1% on average). Such differences are reduced with obesity (18.1%), overweight (22.8%), respiratory infection (20.8%) and age >80 years (26.8%). Improving glycemic control shows increasing costs but at decreasing rates. Modifiable factors (glycemic control, weight status and comorbidities) drive primary care costs the first 10 years. Those factors had a larger effect in costs for males than in for females. Copyright © 2014 IMSS. Published by Elsevier Inc. All rights reserved.