In the last decade, the reflection on the role of knowledge management (KM) in the logistics practice has changed face from enthusiasm and high expectations via disillusionment and unacceptable cost-benefit ratio to some best practices and hesitant implementation. In order to see the full picture behind these spotlights, an empirical research on the relevance of knowledge and KM for executing logistics processes, on the need of investment into knowledge and KM activities in logistics, and on the eventually existent relationship between knowledge and logistics performance was run with logistics companies from different European countries. For the latter, a model has been developed which contributes to an economic assessment of KM and the analysis of its potentials. The paper presents the approach and results of a European impact study, conclusions drawn from the use of the methodology and a list of recommended actions derived from this respectively.