Recently established methodologies for independent design of robust decentralized controllers are limited to open-loop stable processes. To facilitate independent design for open-loop unstable processes, new formulations are developed using the stable factorization approach (Vidyasagar, 1985, Control System Synthesis : A Factorization Approach. The MIT press, Cambridge, MA.). Application of the proposed design procedure to examples reveals that controllers for unstable systems can be designed to contain robustness properties. This result gives the control system designer more insight into the control of unstable processes.