Many companies base their purchasing strategy on purchasing portfolio models, such as the well known Kraljic matrix (1983). However, these models are criticized to be too simple, especially by proponents of the Network Approach. They point at the isolation problem, strategies for the different purchasing groups would be formulated too independently of each other. Since portfolio models are limited to the analysis of products in a purely dyadic context, they cannot capture all aspects that are regarded as vital for buyer-supplier relationships from a network perspective (Dubois and Pedersen, 2002). However, the Network Approach is criticized as well. This approach would be too conceptual in nature and would offer little application possibilities in practice. Up to now, these approaches are not confronted in literature and business practice. In the proposed study will be examined whether and how factors of the business network affect the formation and execution of purchasing strategies. The practical significance of this study is the contribution to the development of the Kraljic Matrix into an integrated conceptual instrument to formulate purchasing strategies. The study includes three phases: (1) and (2): literature review and case studies (refining the model); (2) a survey (to test the conceptual model); (3) a conjoint analysis (insight in the trade- offs in choosing purchasing strategies).