The helminth community of Larus dominicanus (Charadriiformes) is reported from Península Valdés, on the Patagonian coast, Argentina. From March 2000 to April 2004, 29 kelp gulls were collected and dissected. All the birds were parasitized by at least 2 of 18 parasite species: 2 cestodes (1 Tetrabothriidae, 1 Dilepididae), 10 trematodes (2 Echinostomatidae, 3 Microphallidae, 2 Gymnophallidae, 1 Philophthalmidae, 1 Dicrocoeliidae, 1 Diplostomatidae), 4 nematodes (2 Acuariidae, 1 Capillaridae, 1 Anisakidae), and 2 acanthocephalans (Polymorphidae). The mean intensity was 3,204 parasites per host, and all helminths parasitized the gastrointestinal tract or associated glands. The helminth community of L. dominicanus on the Peninsula Valdés coast seems to be richer than those reported by previous authors in other localities in Argentina. This could be due to a greater diversity in prey items available. Nine species are recorded for the first time from the kelp gull and seven species are recorded for the first time from Argentina.