This paper presents collaborative agents system architecture approach for data dissemination in a wireless sensor network (WSN). This system architecture consists of four layers of agents with different types of functionalities, including the interface layer, regional layer, query layer and data collection layer. At the interface layer, the interface agents interact with the users to fulfill their interests. At the regional layer, the regional agents and the cluster agents communicate with each other using TCP/IP protocol and facilitate collaboration between the agents of the other layers. The regional agent generates the optimized query plan to the cluster agent. At the query layer, the query agents perform data dissemination and efficient in-network processing with the other agents in the same layer; it also captures the required data through the data collection layer that has direct access to sensor nodes. This paper provides the agents? architecture, design and implementations that enable them to communicate and work together to disseminate and gather data in WSNs.