In this paper, a Rate Adaptation Scheme (RAS) for media streaming applications, appropriate for future heterogeneous networks is presented. In such environments, vertical handovers across networks with highly diverse characteristics are likely to occur. In these cases, RASs should cope with abrupt network resources variations. Existing rate adaptations mechanisms would fail to adjust, in a timely manner, to the characteristics of the new network or recognise a vertical handover event. The proposed scheme enhances an existing rate adaptation algorithm towards providing uninterrupted streaming sessions to mobile terminals, when moving across networks with diverse characteristics. Applications can adapt their rate, based not only on application level feedback (e.g. packet and frame loss rate), but also on feedback received from a terminal management entity. The proposed scheme is evaluated using extensive simulations, is implemented over an open end-to-end MPEG-4 streaming suite and it is experimentally validated. Copyright © 2007 Inderscience Enterprises Ltd.