Summary: This paper presents the multimedia C language, which is designed for the multimedia extensions included in all modern microprocessors. The paper discusses the language syntax, the implementation of its compiler and its use in developing multimedia applications. The goal was to provide programmers with the most natural way of using multimedia processing facilities in the C language. The MMC language has been used to develop some of the most frequently used multimedia kernels. The presented experiments on these scientific and multimedia applications have yielded good performance improvements.