The shallow-water hydroids and hydromedusae from the fjords region of southern Chile are surveyed. A total of 63 species
are described or mentioned. Of these, one species, Halecium fjordlandicum sp. nov., is new to science, five species
could be identified to genus only, and one species, Hebella cf. dispolians (Warren, 1909), is only tentatively identified.
The species have been assigned to nine families of athecates, 13 families of thecates, two families of narcomedusae and
one family of trachymedusae. Among the present material, twenty species are new records for Chile: Bougainvillia muscoides
(M. Sars, 1846), B. pyramidata (Forbes & Goodsir, 1851), Cordylophora caspia (Pallas, 1771), Hydractinia
tenuis (Browne, 1902), Eudendrium cf. nambuccense Watson, 1985, E. cf. scotti Puce, Cerrano & Bavestrello, 2002,
Calycella syringa (Linnaeus, 1767), Campanulina pumila (Clark, 1875), Egmundella gracilis Stechow, 1921, Lafoeina
longitheca Jäderholm, 1904, Filellum cf. magnificum Peña Cantero, Svoboda & Vervoort, 2004, Hebella cf. dispolians,
Sertularella argentinica El Beshbeeshy, 1991, S. fuegonensis El Beshbeeshy, 1991, S. gayi (Lamouroux, 1821), S. jorgensis
El Beshbeeshy, 1991, Campanularia cf. hincksii Alder, 1856, Clytia linearis (Thornely, 1900), C. paulensis (Vanhöffen,
1910) and Cunina octonaria McCrady, 1859. A number of species show affinities partly with the cold-temperate
Magellan region, and partly with Antarctica. The remaining species have either a cosmopolitan distribution, or are
restricted to the temperate part of the southern hemisphere. Finally, several species have a bipolar distribution. Two species,
Hydractinia pacifica Hartlaub, 1905 and Kirchenpaueria magellanica (Hartlaub, 1905) are here recorded for the
first time from Chile since their original description. Phialella chilensis (Hartlaub, 1905) is regarded as a synonym of P.
quadrata (Forbes, 1848), since there are available records of the medusa stage of the latter species from Chile. Some of
the well-known species are listed together with short remarks, while others are briefly described. Less common species
are redescribed, and new and uncertain species are fully described. Nearly all the species are illustrated, and their geographic
distributions along the coasts of Chile are indicated. A checklist of all hydroids and hydromedusae described or
mentioned from Chile is provided. Deposition of alcohol-preserved specimens and microslide preparations in the collections
of the Muséum d’Histoire Naturelle of Geneva is indicated.