This thesis investigates how buyers can successfully manage dyadic buyer-supplier relationships. Research has provided solutions for managers about which relationship type is the most appropriate and beneficial for buyers in particular circumstances. Different relationship types were examined and key factors affecting relationship management and their effect on it were investigated. A deductive approach was undertaken, i.e. an innovative framework of relationship management and related hypotheses were generated on the basis of a thorough literature review. Then these hypotheses were tested with the use of case studies. An original framework filled the gaps in the literature and contributed to the body of knowledge since its dimensions are based on the most important influencing factors; namely, the availability of alternative sources of supply and the purchased product contribution to current and future profit. The framework is unique because it proposes relationship types and takes into account the power issue. The framework encourages managers to plan into the future and assess influencing factors, taking into account changes in the external and internal business environment, which have been ignored by established writers. The results have shed new light on relationship management. It was found that the relationship management of any product category cannot be ignored, since seemingly unimportant purchasing may bring significant savings related to a buyer's high bargaining power if relationships are appropriately managed. Importantly, it was concluded that closer relationships should be developed when product development time is longer, higher volumes are purchased from a single supplier, purchases are more complex and/or critical, their functionality and quality are more important and can be influenced, and if responsiveness to changing consumer tastes is required. Finally, using the results obtained, an improved framework of relationship management has been developed, in which two "best for the given situation" relationship types are proposed for a particular scenario based on the factors listed above. The application of the framework will help to: increase a company's profitability, improve relationship management, improve the functionality of purchases, improve the performance of organisations and of its suppliers, as well as increase efficiency and effectiveness.