Background & Aim: Achillea (Fam. Asteraceae) is a medicinal plant and different species of it have several uses in the folk medicine all around the world. Achillea species are used for feverish conditions, common cold, digestive complaints, slow healing wounds and skin inflammations. This study aims to investigate the essential oil composition and antioxidant activities from the aerial parts of Achillea eriophora collected from Khash city in Sistan and Baluchestan province. Experimental: Chemical composition of the essential oils was obtained by hydro-distillation method using a Clevenger type apparatus and analyzed by GC/MS. Results and Discussion: In the essential oil of Achillea eriophora 33 compounds representing 100%, were identified in which Camphor (21.55 %), Artemesia ketone (13.84%), Alpha-Thujone (11.85%), Borneole (8.94%), Yomogi alcohol (7.74%), 1,8-cineole (5.19%), Terpinene-4-ol (4.23%) and Myrtenol (3.10%) were the major constituents. In addition, the antioxidant activity of ethyl acetate and ethanolic extracts of Achillea eriophora was analyzed using the 1, 1-diphenyl-2- picrylhydrazyl (DPPH) free radical scavenging. According to antioxidant activity outcomes, the amount of IC50 of ethyl acetate and ethanolic extracts of the aerial parts of Achillea eriophora and also butylated hydroxyl toluene (BHT) as a standard was 245.20 ppm, 89.25 ppm and 45.58 ppm, respectively. Ultimately, it was highlighted that the antioxidant activity of ethyl acetate extract was weaker than ethanolic extract. The antioxidant activity of both of them were also weaker than BHT as a synthetic antioxidant. Some compounds like 1, 8-cineole and terpinen-4-ol can be responsible for antioxidant and antimicrobial activity, while Camphor and borneol have not been proven to be strong antioxidant agents as emphasized elsewhere. Recommended applications/ industries: The results of the present study showed that Achillea eriophora from Sistan and Baluchestan may be considered as source of natural antioxidant to be used in medicinal and food products to promote human health and prevent diseases. پرونده مقاله