The fatty acid composition is species and tissue specific, however it is susceptible to change depending on the diet and the metabolical processes inside the organism. The fatty acid composition of milk is of exceptional importance for the quality of milk, and approximately half of the fatty acids in the milk are sourced from the blood. The main focus of this thesis was to determine the differences in the fatty acid profile of goat serum and milk, depending on the brood size and various phases of the production cycle. The research was carried out on 30 clinically healthy Saanen goats. After the extraction of total lipids from the serum and milk samples, the analysis of methyl esters of fatty acids was performed using gas chromatography (GC). Predominating in milk and serum are the saturated fatty acids (SFA), with C16:0 being the most common, regardless of the litter size or the lactation stage. In dry period, a much smaller percentage of serum unsaturated fatty acids (UFA) was determined compared to the lactation period (p<0,050), and in the milk, during the early lactation, there were much less monounsaturated fatty acids (MUFA) than during the late lactation. Some differences were also found in individual fatty acids in the serum and the milk in various production stages. In late lactation, there was a higher percentage of C16:0 and C18:0 (p<0,050) in the serum of goats with one kid. During early lactation in the milk of goats with one kid there were less (MUFA), C18:1c9, C8:0 and more C12:0 (p<0,050). Based on these results, we could conclude that the lactation period affects the fatty acid composition of goat milk and serum. The litter size affects the fatty acid composition of the milk in early lactation.