Starting from Michael Porter's diagnosis regarding the dynamics of the competitive environment based on five forces and from the perspective of the value chain analysis in achieving the competitive advantage on a cutting edge market, this article proposes an in-depth analysis in the topic of purchasing decisions within economic organizations, whose processes need to be approached strategically in order for organizations to develop and evolve properly. Managing in a proper way the relation with the suppliers of goods, raw materials, and services will determine the costs to decrease and thus the revenues and implicitly the profit will grow, placing the entity on a good track in fighting with competition and bringing benefits for all its stakeholders. Moreover, taking into account that the environment in which organizations operate is often surrounded by uncertainty, the decisional process, especially the strategic one, is characterized by ambiguity, doubled also by the subjectivity of the human factor in decisional reasoning. In this context, choosing the right supplier according to specific selection criteria represents the most important decision of the purchasing function. Sometimes, it requests the implementation of qualitative mathematical methods such fuzzy logic, which is a powerful tool that can efficiently shape the ambiguity within decision-making process and support the organization long-term strategy and competitive market positioning.