Despite the extensive use of Mumps virus vaccines for almost forty years, there is still a paucity of knowledge concerning the Host-Pathogen Interaction. This paper reviews the advances in our knowledge of the antiviral immune response with particular reference to the selection of attenuated mumps virus strains used in different vaccine formulations. The ability of mumps viruses to evade the interferon component of the immune response is described in detail. This study also presents recent findings from our laboratory and others concerning the humoral and cell mediated responses to mumps virus. Particular attention is placed on mumps virus induction of interleukin-10 (IL-10) and the potential for this to be a novel immune evasion strategy is discussed. Finally, recent advances in our understanding of the immune response to mumps virus are placed in the broader context of our current understanding of this disease.