—Mobile sensors are widely deployed in Wireless Sensor Networks (WSNs) to satisfy emerging application requirements. Specifically, processing location dependent queries in mobile WSNs is still a challenging problem due to sensor mobility. We present an Event-based Location Dependent Query (ELDQ) model that continuously aggregate data in specific areas around mobile sensors of interests to provide event-based location dependent data services to the users. ELDQs generalize several typical query types and are important in many applications. However, existing approaches are incapable of efficiently answering ELDQs. In this paper, we propose a set of techniques to process ELDQs while optimizing system performance. Cost analysis and simulation results indicate that our techniques greatly reduce the cost of processing ELDQs while achieving relatively high accuracy and short response time.