The lipooligosaccharide (LOS) locus class was determined using polymerase chain reaction (PCR) in 335 Finnish Campylobacter jejuni strains isolated from humans, poultry and bovines with known multilocus sequence types. The results revealed an association between clonal complexes/sequence types (STs) and LOS locus classes. Based on these results, we further predicted the LOS locus classes distribution among the STs of 209 additional C. jejuni strains from Finnish human domestically acquired infections. Non-sialylated LOS locus classes were associated with STs that comprised ≈55% of patient strains. Sialylated LOS locus classes A and B were associated with STs infrequently isolated, whereas class C was correlated with the ST-21 complex, found in ≈14% of human strains. A combination of the LOS locus class and multilocus sequence type may provide new information on the epidemiology and association of C. jejuni strains with certain disease outcomes.