The aim of my thesis was the determination of fatty acid content in the oils using mass spectrometry. I investigated the distribution of the fatty acid composition in beard oil, coconut oil, fish oil, palm oil and sunflower oil using GC-MS. Saponification was used as the first step in sample preparation and then I prepared the free fatty acid. HCl and Methanol is added to the sample to produce the FAMEs (Fatty acid methyl esters) done by acid catalyzed process. After this I identified these fatty acids by comparing their retention times to the FAMEs standard. Also using the chromatogram obtained from this experiment I could compare the compounds with the similarity search in the mass spectra library. Based on this I identified the various fatty acid compounds and determine the name.