This master’s thesis examines practical problems in supplier relationship management activities and especially decision-making practices in this field. Growing supplier base caused significant difficulties when decisions concerning its strategic development are needed. The aim of the study is to explore supplier relationship management system of the case company and develop decision-support tool to enhance managerial efficiency. The paper deals with the existing theoretical and practical researches in this area, on the basis of which the new tool suited to the task was developed and applied. The thesis has theoretical and empirical parts. The former one comprises theoretical studies and practical models from previous research relevant to the topic. Empirical part represents business background of the company and proposes a decision-support tool which helps the firm to manage its suppliers.