Omega – 3 fatty acids are special group of unsaturated fatty acids. They are oft described as valuable fat because of their importance for human health. They are crucial for heart, blood vessels, brain and joints health. They also positively affect the mood and enhance the antidepressants action. Omega – 3 fatty acids are essential, which means that the organism can´t produce it by itself, and therefore we have to eat more often food that contains omega – 3 fatty acids. The best sources of omega – 3 fatty acids are fish, flax seeds, soya bean, canola and walnuts. There is a large number of scientific publications that describe methods for determination and analysis of omega – 3 fatty acids in different type of groceries. That is a huge step forward in human nutrition and health care. In experimental research extraction is most commonly used for isolation of omega – 3 fatty acids from plants and animals and the most commonly used are green extraction methods, i.e. extraction with supercritical CO2 and others. Most popular methods of analysis and detection of omega – 3 fatty acids are chromatography methods. Mostly used chromatography method is GC – MS method which unites gas chromatography and mass spectrometry. It is important to say that all methods for omega – 3 fatty acids determination are in further development and with each new research scientists want to achieve better results.