This paper presents an agent based system to increase the life time of node in Wireless Sensor Networks. In wireless sensor network nodes deployment of nodes is random and on large scale. This kind of deployment gives birth to massive sensory data which is redundant in nature. Routing of such kind of unnecessary data not only saturates network resources, but also consumes immense nodes energy. We unadulterated our efforts to enhance the node life time in sensor network by introducing mobile agents. Mobile agents are used to reduce the communication cost, especially over low bandwidth links, by moving the processing function to the data rather than bringing the data to a central processor (sink). Toward this end, we propose our agent based directed diffusion approach. Furthermore, to have better understanding in evaluating the performance of both approaches, we present detailed analytical model of data dissemination for both. The results of our simulation show that agent based directed diffusion provides better performance than directed diffusion in terms of energy consumption and bandwidth saturation.