In recent years, new products obtained from amaranth seeds have entered the food market including expanded “popping” seeds and flakes. Lipids and biologically active substances dissolved in these products are susceptible to changes. Additionally, due to the fact that fat quality has high dietary importance, there is a need to conduct detailed quality and quantity studies on the lipid composition of Amaranthus cruentus. For the samples under analysis, protein, fat, starch and ash content were determined. Fatty acids and sterols were analysed by gas chromatography. The analysis of tocopherols and squalene content was carried out with the application of high-performance liquid chromatography coupled with photodiode array and fluorescence detectors (HPLC-DAD-FLD). Protein, fat and starch content did not change during seed processing. However in the case of tocopherols, the total tocopherol content was 10.6 mg/100 g for seeds, while in “popping” and in flakes it was reduced by approximately 35%. The squalene content ranged from 469.96 mg/100 g for seeds to 358.9 mg/100 g for flakes. No significant differences were observed in the fatty acid profile of seeds and products, but differences were observed in the sterol content.