Component-Based Development (CBD) reduces development time and effort by allowing systems to be built from pre-developed reusable components. A classical approach to reduce embedded systems design and run-time complexity is to partition the behavior into a set of major system modes. In supporting system modes in CBD, a key issue is seamless composition of multi-mode components into systems. In addressing this issue, we have developed a Mode Switch Logic (MSL) for component-based multi-mode systems, implementing seamless coordination and synchronization of mode switch in systems composed of independently developed components.