The composition of the volatile fraction of 164 Italian sweet orange oils, laboratory-prepared from fruits of different cultivars, has been studied by GC and GC/MS. The following cultivars have been examined: Biondo comune, Navelina, Washington navel, Ovale, Valencia late (blond cultivars) Tarocco, Moro, Sanguinello (blood cultivars). The average composition of each of the cultivars is reported as is the standard deviation for each compound. As a result, the behavior of the classes of substances and of some of the components during the period analyzed are shown. Furthermore, the results are compared with those of previously analyzed commercial sweet orange oils.