This paper describes a multi agent system (MAS) for distributed composition of Semantic Web services. Since our system is intended to function in highly dynamic environments, where heterogeneous agents rapidly join and leave the system, we consider P2P approach as most suitable for facilitating agent and service discovery. The MAS is based on Chord P2P network, which allows the MAS to dynamically publish and locate available Semantic Web services, which are specified with OWL-S. In order to compose new Web services from existing ones, agents apply symbolic reasoning in a cooperative problem solving manner.