Plant kingdom contains about 620 families. One of them is family lamiaceae which has spearmint plant. This plant has a pungent taste with digestive effects. Phytochemical screening, chemical composition and antioxidant activity of spearmint aerial parts methanolic extract were investigated. Phytochemical analysis indicated the presence of terpenes, tanins, flavonoids, saponins, glycosides, alkaloids and phenolic glycosides. Total phenolic and flavonoids contents of the methanolic extract were found to be 35.65mg gallic acid equivalent (GAE)/g and 27.47mg quercetin equivalent (QE)/g respectively. Different antioxidant procedures were used to determine the activity of spearmint as antioxidant such as: DPPH, antioxidant capacity, nitric oxide radical scavenging, superoxide dismutase activity, hydroxyl radical scavenging and reducing power assay.