Chemical investigation of the Antarctic lichen Usnea aurantiaco-atra led to the isolation and identification of eight compounds, including a dibenzofuran derivative (1), three phenolics (2, 7, 8), a p-terphenyl (3), and three sterols (4-6). The structures of the isolated compounds (1-8) were elucidated by 1H and 13C NMR spectroscopic ana-lyses and comparisons with previously reported data. All compounds (1-8) were isolated from this species for the first time. The current study is also the first report of the identification of two compounds, pentamethoxy-p- terphenyl and 9,11-dehydroergosterol peroxide, from the Usnea genus. Meanwhile, the chemotaxonomic value of all isolates is also discussed in this paper. Usnea aurantiaco-atra, Antarctic lichen, Dibenzofuran, Sterol, p, -Terphenyl, antibacterial activities, phenolic-compounds, acid-derivatives, usnic, acid, antioxidant, metabolism, Biochemistry & Molecular Biology, Environmental Sciences & Ecology, Evolutionary Biology