In present study, we report phenolic compounds and antioxidant activity of decoction and infusion of Mentha spicata L. subsp. spicata and M. longifolia (L.) L. subsp. typhoides (Briq.) Harley. The quantitative amounts of the phenolic contents were determined by LC-MS/MS. The main compounds and amounts of M. spicata were determined as follow for decoction; caffeic acid, quercetagetin-3,6-dimethylether and penduletin (4126.6; 2141.5; 1472.7 mg/kg dried herba, respectively), for infusion; fumaric acid, t-ferulic acid and caffeic acid (4220.1; 1148.7; 1064.1 mg/kg dried herba, respectively). While phenolic compounds in M. longifolia decoction were presented as follow; rosmarinic acid, luteolin and quercetagetin-3,6-dimethylether (1570.7; 460.9; 420.2 mg/kg dried herba, respectively), for infusion; rosmarinic acid, luteolin and fumaric acid (620.9; 518.2; 489.8 mg/kg dried herba, respectively). Also the antioxidant activities were determined based on three methods: 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, β-carotene linoleic acid assays and cupric (Cu2+) ion reducing power assay (CUPRAC). For all the activity assays, infusion and decoction of the samples showed good activity.