Plants have been significant source of drugs with potential for thousands of years. Phytochemicals are the chemicals extracted from plants. These organic chemicals are classified as primary or secondary constituents, depending on their role in plant metabolism. [1] GC-MS method used for the analysis of the obtained extract can be an interesting tool for testing the amount of some active principles in herbs used in various industries. [2] The main objective of the study was to evaluate the fatty acids composition for identified bioactive compound in leaf hexane extract of the Abutilon pannosum and Grewia tenax was analysed by gas chromatography combined with Mass Spectrometry. While the mass spectra of the compounds found in the extract was matched with the National Institute of Standards and Technology (NIST) library. Fatty acids play a crucial role in growth and development of the body. It is known to have antibacterial and antifungal properties. [3]The shade dried both plant leaf powder was extracted with hexane by using Gerhardt Soxhtherm extractor and crude hexane extract was obtained. Derivatization was performed and then gas chromatography-mass spectrometry (GC-MS) was done for detecting fatty acids. From that eleven phytochemical constituents have been identified. The GC-MS analysis revealed the presence of various compounds like 9, 12-Octadecadienoic, 9-Octadecenoic acid, Hexadecanoic acid, Octadecanoic acid, Octadecatrienoic acid, 9, 12, 15- Eicosanoic acid, 9-Hexadecenoic acid, 11-Eicosenoic acid, Methyl tetradecanoate, Octanoic acid and Tridecanoic acid. These findings support the traditional use of A. pannosum and G. tenax in various disorders.