SUMMARYNCX is an extended C language for data-parallelism, which is one of the most important computation models to support realistic applications of massively parallel computers. The design criteriaof the language include easy shifting from C language, low-cost implementation of efficient compilers, and high integrity as a programming language. The language is based on the concept of virtual processors, each being powerful enough to execute the full-set C language. Several features for data-parallel computation, such as interprocessor communication, are added to the language so that obey the design principles of the base language C. The language is intended to be used on various architectures and is now being implemented for some machines with different architectures. This paper overviews the major extended features of NCX, together with some programming examples, and shows that NCX provides sufficient expressive power for dataparallel computation while it is based on the simple and clear notion of virtual processors.