Two groups of three week old Herring Gulls (Larus argentatus) were held to observe the carrier state with Campylobacter. All 27 birds of group I excreted Campylobacter jejuni biotype 1ZZ when they were caught from their colony. Four weeks later all but one were negative, indicating that the carrier state lasts until about the seventh week of life, with self-elimination if infection with another Campylobacter species is prevented by housing in a closed environment as in this study. Only one bird became reinfected one year later when gulls from group I were brought into contact with gulls from group 11, consisting of ten freshly caught gulls, four of which were infected with the same biotype of Campylobacter, indicating that there might he some kind of immunity protection against infection with the same biotype of Campylobacter spp.