The aims of the study were to investigate the presence of phytochemical compounds from the leaves of Rosmarinus oficinalis, using methanolic extraction and report the main functional components by using FT-IR. The phytochemical compound screened by GC-MS method. Seventeen bioactive phytochemical compounds were identified in the methanolic extract of R. oficinalis. The identification of phytochemical compounds is based on the peak area, retention time molecular weight, molecular formula, chemical structure, MS Fragment ions and pharmacological actions. GC-MS analysis of Rosmarinus oficinalis revealed the existence of the ?-pinene, Camphene, Eucalyptol, 2-Methoxy-4- vinylohenol, 1-Oxaspiro[4,5]deca-3,6-diene,2,6,10,10-tetramethyl, 1-Oxaspiro[4,5] deca-3,6- diene,2,6,10,10-tetramethyl, Neocurdione, Isoaromadendrene epoxide, 1b,4a-Epoxy-2Hcyclopenta[ 3,4]cyclopropa[8,9] cycloundec., Cis-Vaccenic acid, Phenanthrenol,4b,5,6,7,8,8a,9,10- octahydro-4b,8,8-trimethyl-1, Galanthamine, Dibenz[a,c]cyclohexane,2,4,7-trimethoxy, 2,4a,7- Trihydroxy-1-methyl-8-methyleneqibb-3-ene. 1,10-carboxylic acid, Retinoic acid, 7,8,12-Tri-O-acetyl-3- desoxy-ingol-3-one and 4,6-Androstadien-3?-ol-17-one,acetate. The FTIR analysis of Rosmarinus oficinalis leaves proved the presence of Alkenes, Aliphatic fluoro compounds, Alcohols, Ethers, Carboxlic acids, Esters, Nitro compounds, Alkanes, Aldehydes, Ketones compounds. It contain chemical constitutions which may be useful for various herbal formulation as anti-inflammatory, analgesic, antipyretic, cardiac tonic and antiasthamatic.