One of the major setback preventing the mobile agent technology from being widely exploited is a lack of interoperability between heterogeneous mobile agent systems. In this paper we propose a Java-based framework which enables high-level interoperability between Javabased mobile agent systems. The framework relies on an event-driven, proxy-based mobile agent model and allows for supporting interoperable mobile agents which can be easily coded and adapted to existing mobile agent systems without any modifications of their infrastructures. We tested our framework for enabling interoperability among the Aglets, Ajanta, Grasshopper and Voyager systems. The experimentation results showed that high efficacy is obtained by keeping the efficiency overhead acceptable for heterogeneous computing environments. Keywords. Mobile Agents, Events, Proxy-based Coordination Model, Mobile Agent Interoperability, Agent Frameworks.