Abstract. Grid monitoring systems collect a substantial amount of information on the infrastructure’s status in order to perform various tasks, more commonly to provide a better use of the grid’s entities. Modern computational and data grids have become very complex by their size, their heterogeneity, their interconnection. Monitoring systems as any other grid’s tools have to adapt to this evolution. In this paper we present a decentralized, scalable, and autonomous grid monitoring system able to tackle the growths of scale and complexity. System’s components communications are hierarchically organized on a peer-to-peer overlay network. Fresh information is efficiently propagated thanks to an directed gossip protocol that limits the number of message. Automation of key management operations eases system administration and maintenance. This approach provides scalability and adaptability. The main properties of our application are presented and discussed. Performance measurements...