The present study was to investigate the essential oil composition and the antioxidant evaluation of P. inuloides growing the Algerian Sahara. The chemical composition was determined using GC-MS method, and antioxidant properties were estimated by DPPH and β-carotene assays. The major components were δ-cadinene (24.0%), α-epi-cadinol (15.0%), α-cadinol (12.7%), α-muurolene (7.8%) and γ-cadinene (6.6%). The highest antioxidant activity by DPPH and β-carotene assays were reported for the ethyl acetate extract (IC 50 = 14.4 µg/mL and 85.2%) which was also the most concentrated in total phenol and flavonoid contents (316.5 µgGAE/mg and 396.8 µgEQ/mg, respectively). The essential oil showed also a high antioxidant potential by β-carotene assays (85.3%). Furthermore, the present work represents the first report on the essential oil constituents of an Algerian P. inuloides.