The purpose of the paper is to contribute to the knowledge in the field of marketing of medical devices in the public sector. The research problem is based on verifying the correlations between the elements of the 4P marketing mix, after-sales activities and their influence on the preparation of tender documentation in the marketing of medical devices to social welfare institutions. In the process of marketing products through public procurement, the same attention is devoted to the after-sales activities as marketing mix elements (4P). We created a marketing mix model for the marketing of medical devices through public procurement.