Massive Multiplayer Online Games with their virtual gaming worlds grow in user numbers as well as in the size of the virtual worlds. With this growth comes a significant increase of the requirements for server hardware. Today an MMOG provider usually faces the problem of serving thousands of users with entire server clusters. Peer-to-Peer networks with their high scalability and flexibility meet the requirements of connecting hundreds of thousands of people all over the world without a central server. In doing so the network bandwidth requirements remain at a reasonable level. In this work we propose to combine MMOGs with a Peerto-Peer network. We introduce a game architecture capable of exploiting the flexibility and scalability of P2P networks. A P2P architecture based on an overlay network using distributed hash tables with support for persistent object storage and event distribution has been developed to meet MMOG requirements. Keywords MMOG, peer-to-peer, game architecture