In this study evaluated the phenolic, flavonoid contents, antioxidant, antimicrobial and cytotoxic activities of Achillea coarctata extract. Also, chemical compositions of the extract and essential oil were analyzed by HPLC and GC-MS. The antioxidant activity of the extract was determined with phosphomolybdenum, DPPH (2,2-diphenyl-1-picrylhydrazyl radical scavenging), hydrogen peroxide scavenging, beta-carotene bleaching activity, Fe+2-ion reducing power (FRAP) and cupric ion (Cu2+) reducing antioxidant capacity (CUPRAC) assays. The extract and essential oil were investigated for antimicrobial activities against 15 species of microorganisms. The extract has been only found to be effective against Klebsiella pneumoniae, while essential oil was effective against Listeria monocytogenes, K. pneumoniae, Bacillus cereus, Streptococcus pneumoniae and Candida albicans. The cytotoxic activity of the extract on MCF7 (human breast cancer cell line, ATCC HTB-22) and NIH/3T3 (mouse embryo fibroblast cells, ATCC CRL-1658) was studied by MTT assay. The extract showed cytotoxic activity on MCF-7 cell line.