mxkssd is a package that generates efficient mixed-level k-circulant supersaturated designs by interchanging the elements of the generator vector. The package tries to generate a supersaturated design that has E(fNOD) efficiency more than user specified efficiency level (mef). The package also displays the progress of generation of an efficient mixed-level k-circulant design through a progress bar. The progress of 100% means that one full round of interchange is completed. More than one full round (typically 3-4 rounds) of interchange may be required for larger designs.