Essential oil are very interesting natural plant products and among other qualities they posses various properties depend on the composition in the essential oil, so it is important to know that composition, which give idea for the toxicology and safety of essential oil. Therefore, the chemical characterization of the essential oil is very important for the understanding of its properties. The literatures show and to our knowledge no previous reported on the Al- Habak (Mentha longifolia) have been study for different location in KSA by GC-MS. Al-Habak (Mentha Longifolia) were collected from different location in Kingdom of Saudi Arabia (KSA) were subjected to the hydrodistillation extraction for the essential oils, the oil submit to qualitative and quantitative analysis using Gas chromatography- Mass Spectrometer (GC-MS) techniques equipped with a fuse silica capillary column. The instrument will be optimized in term of the temperature programme for the GC oven and the effective parameter for MS. The identification will carried out by computer matching with the NIST library as well as by comparison the retention time with standards. A total of 49 compounds were identified in the essential oils extracted from Al-Habak plant represented 99.96-100% of the total oil compositions, with pulegone (11.92- 62.54%), menthone (7.84-34.13%) as the main constituents found in all samples.