The structure of a short-chain lipopolysaccharide (LPS) of Vibrio cholerae O22 strain 169-68, that cross-reacts with V. cholerae O139 Bengal, was elucidated. The structure differs in detail from that reported on another strain of O22 [A.D. Cox, J-R. Brisson, P. Thibault and M.B. Perry, Carbohydr. Res., 304 (1997) 191-208]. The similarity and difference between the LPS structures of the two strains as well as between O22 and O139 are discussed.