the chemical composition of the essential oils of two new citrus hybrids, obtained by crossbreeding the diploid clementine citrus clementina hort. ex tan. and the tetraploid orange citrus sinensis (l.) osbeck cv. tarocco, was studied by gc/ms. in all, 42 components were fully characterized and grouped into four classes (monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpenes, and aliphatic aldehydes and alcohols) for an easier comparison with the oils of the parents. since limonene is by far the main component of all the essential oils examined, representing generally ca. 95% of the total, significant hybrid-hybrid and parent-hybrid differences can be observed only within the remaining 5%. these new hybrids are the first example of a mandarin-like hybrid with a red pigmentation, a feature inherited from the tarocco orange. these new fruits, therefore, add further to the very high production of pigmented citrus fruits, which are an almost exclusive patrimony of sicilian citrus production. this pigmentation is due to the presence of anthocyanins, whose known antioxidant activity gives them an important biological role in the disease prevention of living systems. keywords: citrus clementina hort. ex tan.; citrus sinensis (l.) osbeck cv. tarocco; citrus breeding; citrus triploid hybrid; essential oil composition; pigmented citrus fruits