The use of mobile agents for data fusion in wireless sensor networks has been recently proposed in the literature to answer the scalability problem of client/server model. In this article, we consider the problem of calculating a near-optimal route for a mobile agent that incrementally fuses the data as it vis-its the nodes in a distributed sensor network. The order of visited nodes affects not only the quality but also the overall cost of data fusion. Our proposed heu-ristic algorithm adapts methods usually applied in network design problems in the specific requirements of sensor networks. It suggests the optimal number of MAs that minimizes the overall data fusion cost and constructs near-optimal itineraries for each of them. The performance gain of our algorithm over alter-native approaches is demonstrated by a quantitative evaluation.