The goal of this study was to design a methodology for activity-based costing (ABC) for a representative company of the segment of small business and medium enterprises in the bread industry. The methodology consisted of a review of modern contributions of the literature on the application of the ABC approach for three typical products of a bakery company of the city of Chillán, Chile. As a result, a methodology was designed based on six steps and 18 equations that allow the assessment of direct and indirect costs of products that are related to five centers of operation and 13 centers of activity. The main conclusions of this study indicate that with the implementation of the ABC costing it is demonstrated that the costs under the application of the traditional costing system are undervalued with respect to the actual production costs for three types of typical products marketed by the company object of study.