Rainforests are pristine natural ecosystems in the Chilean northern Patagonia, among fjords and the Andes mountain chain. Despite the enormous extension of these forests, there is no information available on vegetation structure or composition in the Huinay area (42°22' S, 72°24'W), which covers an important part of such forest. The aim of this work was to describe plant communities of Huinay's rainforest, by means of Zurich-Montpellier phytosociological method in an altitudinal gradient ranging from 0 to 1150 m. As a result, three main forest formations distributed along an altitudinal gradient were identified. These were defined as evergreen forest (up to 600 m), coniferous forest (600 to 1.000 m) and deciduous forest (1.000 meters and above). Moreover, two unidentified communities, corresponding to the Chiloé-Tepú Coihue, and elfin woods of Lenga, Ñirre and Alerce are also reported. For each forest formation a syntaxonomical position is discussed, as well as the classification of plant communities that compose it, according to the phytosociological clasification schemes proposed for the area. This study is the first step of a complete description and characterization of the community structure of rainforests in the continental fjords from Chilean northern Patagonia.