The coopetition literature argues that coopetition is a dynamic relation that evolves over time but there is a gap when it comes to the understanding of this evolution. The aim of this paper is to investigate, via longitudinal cases studies, the evolution of coopetition relationships and its management at the inter-organizational level. Through multiple cases studies in the same industry (the French grain merchants industry), we reveal the existence of two differing states of the processes of coopetition. The spontaneous coopetition and the deliberate coopetition. Each form of coopetition is related to particular tools that are used by managers in order to sustain a coopetition strategy. These states of coopetition seem to be an evolving phenomenon but this evolution is not systematic and each state of coopetition (deliberate or spontaneous coopetition) can be stable for a while. Using these findings, we propose in this paper some principles and tools to manage the evolution of coopetition.