The elicitation of antibodies to gonococcal lipopolysaccharide (LPS) was studied. Rabbits were immunized with whole cells of gonococci, purified LPS, or LPS linked to bovine serum albumin with glutaraldehyde. Purified LPS was not immunogenic. Anti-LPS antibodies were produced by rabbits receiving the LPS-BSA conjugate. These animals showed an earlier IgG anti-LPS antibody response than animals receiving whole bacterial cells. Antiserum to the LPS-BSA conjugate gave rise to a single precipitation line against ultrasonically disrupted gonococci, and agglutinated heat-treated cells of the bacteria.