SCTP (Stream Control Transmission Protocol) was proposed by IETF. It shows superior extensibility and compatibility as compared to other transport layer protocols, such as TCP and UDP. In addition, it supports multi-streaming and multi-homing. Although an SCTP connection can convey many video streams from different applications, it lacks the provision of different QoS for different streams in the same association. On the other hand, more and more mobile devices are equipped with multiple network (e.g., UMTS/WLAN) interfaces to transmit packets over 3G cellular networks or wireless local area networks. This thesis presents a dynamic chunk adjustment scheme for SCTP-based video streaming in an integrated UMTS and WLAN network. The proposed scheme can support QoS guarantees for different streams in an SCTP association whenever a mobile node moves across the two networks or remains service by either network. Besides, when a mobile node roams from a WLAN to a UMTS, the proposed ¡§deassociation¡¨ capability is applied to increase the channel utilization in 3G cellular networks. Performance evaluations on NS-2 are presented to demonstrate the effectiveness and the advantage of our proposed scheme over the original SCTP.