This paper introduces a open-source free software package, SCILAB, for teaching a typical post-graduate level robust control course. SCILAB is a useful computational tool that may replace high-cost control design and analysis software such as MATLAB. Although SCILAB has been around for a long time, it seems that there is no tutorial available in literature which demonstrates the use of SCILAB for robust control design and analysis. This paper describes the use of SCILAB for the main topics discussed in a typical post-graduate robust control course, including mixed-sensitivity H-infinity control design, H-infinity loop-shaping design and mu-analysis.