Abstract The leaf oil isolated by hydrodistillation from aerial parts of Artemisia campestris L. (Asteraceae) collected from four areas of the south of Tunisia (Bengardane, Benikhdache, Jerba and Tataouine) at three periods of the year 1998 (April, August and November) have been analyzed by GC and GC/MS. Î²-Pinene (24.0â49.8%) was found to be the main component of this oil. Monoterpene hydrocarbons were shown to be the major fraction (58.8â88.6%), and mainly composed of Î²-pinene (24.0â49.8%), Î±-pinene (5.9â12.5%), p-cymene (3.4â9.4%), limonene (4.9â9.3%), (Z)-Î²-ocimene (0.2â5.5%) and Î³-terpinene (2.0â6.5%). Oxygen-containing monoterpenes represented less than 10% of the total oil and was found to mainly contain geranyl propionate (1.6â4.4%), Î±-terpineol (0.6â2.2%) and terpinen-4-ol (0.7â1.9%). Sesquiterpenes ranged from 5.0% to 29.8%. Î³-Muurolene (0.3â5.4%) and Ï-cadinene (0.2â2.4%) were the major sesquiterpene hydrocarbons whereas spathulenol (1.2â8.9%) and Î²-eudesmol (1.0â6.4%) were the main oxygen-containing sesquiterpenes. Samples collected in November were found to be rich in sesquiterpene hydro-carbons (14.4â15.8%) while those collected in August were shown to contain the highest amount of monoterpene hydrocarbons (74.8â88.6%) and the lowest percentage of oxygen-containing components (7.2â18.1%). The variation of the oil composition among origins and periods was not uniform. For all areas, the highest yield of oil was obtained from samples collected in August (1.20%).