Abstract Multimedia computing has emerged in the last few years as a major area of computer science. However, multimedia programming is very hard since programmers need to take into account many complex facilities such as real-time processing, media synchronization, and dynamic QOS control. Since usual programmers take a long time to understand these facilities, multimedia toolkits that can hide such complex facilities from programmers should be provided for making multimedia programming easier. The toolkit should also provide mechanisms for implementing large continuous media applications. Especially, programmers may expect to reuse existing applications for building their applications quickly. If continuous media applications can be constructed by composing a small number of big modules, programmers can create continuous media applications very quickly. In this paper, we describe a continuous media toolkit that has been developing at Multimedia and Mobile Computing Group at Japan Advanced Institute of Science and Technology. The continuous media toolkit has the following two characteristics. Application programmers do not need to take into account real-time processing, media synchronization, and dynamic QOS control since the continuous media toolkit hides such complexities from programmers. The toolkit provides a scripting language that enables programmers to reuse existing programs. Thus, programmers can create multimedia applications by modifying a small part of existing programs. Our toolkit is implemented on Real-Time Mach Microkernel. Currently, several continuous media applications are created for demonstrating the effectiveness of our toolkit.