In this paper, we present a SoC design methodology joining the capabilities of UML and SystemC to operate at systemlevel. We present a UML 2.0 profile of the SystemC language exploiting the MDA capabilities of defining modeling languages, platform independent and reducible to platform dependent languages. The UML profile captures both the structural and the behavioral features of the SystemC language, and allows high level modeling of system-on-a-chip with straightforward translation to SystemC code.