In this thesis we intend to propose and implement a planning based enhancement of the agent oriented programming language CLAIM, in which an agent is an intelligent and mobile entity. This new language which is called P-CLAIM, should have the following characteristics. Firstly, temporal planning capability for the agents. Secondly, the agents should be able to work in a stable manner in the changing environment. Thirdly, a balance should exist between reactivity and proactivity. Fourthly, the agents' actions should not conflict with the actions of other agents in the same environment and the agents should avail the cooperative oppurtunities offered by other agents and they themselves should be able to help other agents where possible.