This article presents the very first phytochemical investigation on new species Tripleurospermum insularum Inceer & Hayirlioglu-Ayaz. The volatile profile of odorous parts of the plant was analysed by GC/MS, and compounds were identified in headspace and essential oil obtained from aerial parts, representing 70.81% and 92.44% in total, respectively. The major volatiles were n-alkanes (38.43-59.22%), while essential oil was also rich in globulol (13.45%) and beta-sesquiphellandrene (9.29%). The content of phenolic compounds in methanolic extract and oil was 3621.62 and 14.4mg GAE/100g of dry plant, respectively. Moreover, potential medicinal effects were found in mean of antioxidant activity of this plant measured by using two different assays: radical-scavenging activity and ferric-reducing activity. Samples revealed values ranging from 0.33 to 146.80 mu mol TE/100g for DPPH assay, and from 2.29 to 5414.17 mu mol AAE/100g for FRAP assay.