The genetics of the biosynthesis of Vibrio cholerae lipopolysaccharide (LPS) are discussed in this chapter. While not much information is available in the literature on the genetics of the biosynthesis of lipid A of V. cholerae, the available information on the characteristics and proposed functions of the core polysaccha-ride (core-PS) biosynthetic genes is discussed. The genetic organization encoding the O-antigen polysaccharides (O-PS) of V. cholerae of serogroups O1 and O139, the disease-causing ones, are described, along with the putative functions of the different constituent genes. The O-PS biosynthetic genes of some non-O1 and non-O139 serogroups, particularly the serogroups O37 and O22, and their putative functions are discussed briefly. In view of the importance of the serogroup O139, the origination of the O139 strain and the possible donor of the corresponding O-PS gene cluster are analyzed with a view to providing knowledge of (i) the mode of evolution for different serogroups and (ii) the possible emergence of pathogenic strain(s) belonging to non-O1, non-O139 serogroups. Finally, the unsolved problems in this area of research and their probable impact on the production of an effective cholera vaccine are outlined.