The use and interest in industrial hemp oil (Cannabis sativa L.) is increasing as it contains a lot of unsaturated fatty acids and has a specific sterol composition. The purpose of the master's thesis was to establish a method with which we could verify the botanical purity of hemp oil based on its fatty acid and sterol composition. We also examined whether one can recognize forged oil based on the comparison of the compositions of pure hemp oil and hemp oil with the addition of another oil, and what quantities of other oils cause a perceptible change in the composition of hemp oil. The fatty acid and sterol composition were determined by gas chromatography with a flame ionization detector. Based on both compositions, we used chemometry to show how oil mixtures (forged oils) differ from each other and from pure hemp oil. The combined results of the regularized discriminant analyses showed that on the basis of sterol and fatty acid compositions it is no longer possible to determine whether the hemp oil is pure or forged when the added oil content is equal or less than 5,3 % (w/w). The fatty acid as well as the sterol composition of hemp oil certainly changes when the content of added oil (sunflower, soybean, rapeseed) is above 9,3 % (w/w).