36 male rats with a life mass of 48±2g were distributed among a depletion, a pair fed and an ad libitum control group. The depletion animals were fed with a Zn‐deficient diet having a Zn content of 1 mg/kg. For the control and pair fed animals the diet was subsituted with 70 mg Zn/kg diet. The duration of the treatment was 20 days. As parameters the concentrations of different fatty acids in liver and brain was determined. The concentrations of the determined fatty acids in the liver were influenced markedly by the food consumption and in a smaller extend by the Zn supply. In the brain the concentrations of 18: 0, 18: 1, 18: 2, 18: 3, 20: 0, 22: 0, 22: 4, 22: 6, 24: 0 and 24: 1 were higher in Zn‐depleted animals in comparison to the ad libitum control animals. The contents of these fatty acids were usually between the two groups. The concentration of the residual fatty acids were not different between the treatment groups.