<p><i>Clostridium chauvoei</i> is a gram-positive spore-forming anaerobic bacterium and the cause of blackleg, a highly fatal endogenous disease in ruminants. The bacterium produces both cellular (somatic and flagellar) and soluble antigens (toxins) that contribute to the pathogenesis. Immunity to <i>C. chauvoei</i> is primarily anti-bacterial, and so the traditional vaccines are formalinized whole-culture bacterins. The current research focuses on identifying specific antigens as immuno-protective antigens including cell surface or flagellar proteins or soluble antigens. This paper summarizes the application of <i>C. chauvoei</i> immunogens for detection or vaccine quality control, and reviews the ongoing research into developing more targeted subunit vaccines using recombinant or purified antigens like CctA or flagellin. Despite high genomic similarity in virulence factors among <i>C. chauvoei</i> strains, differences in the <i>fliC</i> gene encoding flagellin exist. Hence, strain differences may affect the protection efficacy against Blackleg disease. The development of effective Blackleg subunit vaccines necessitates careful consideration of the <i>C. chauvoei</i> strain, antigen purification techniques, bacterial growth phase and the preservation of crucial conformational epitopes in recombinant technology.</p>