Mycobacterium leprae, the etiologic agent of leprosy, until now has not been grown in vitro, resulting in exceedingly obstacles for the production of purified antigens. It is therefore of interest to clone the relevant M. leprae antigens in other easy to handle microbial hosts. Here, we describe two different systems for expressing the 18kDa antigen of M. leprae in S. cerevisiae. Each system was shown to be effective in antigen expression, but the secretion system provided easier purification. Working with different host strains under different growth conditions, large quantities of biologically active proteins were obtained.