This paper presents an approach for designing a robust tracking controller for a two degree of freedom series mass-spring-damper system. Our approach uses the newly developed technique of model reference robust control for SISO systems first described by Qu and Dawson (1992) and more recently by Qu et al. (1992), and we specifically show how this technique can be applied to a common benchmark problem (Wie and Bernstein 1990) for robust control design. This problem is the development of a control that can force the last degree of freedom (i.e. end point) of a mass-spring-damper system to follow a desired trajectory. For this problem we show how a robust controller can achieve global uniform ultimate boundedness (GUUB) for the position tracking error of the system’s last degree of freedom in spite of unknown model parameters and additive bounded disturbances.