The purpose of supplementing feed mixtures with various additions is not only to modify the chemical composition of meat to be produced, but, also, to improve the slaughter value. Therefore, it was attempted to assess the post-slaughter value of animals fed a feed supplemented with flax seeds. The fattening period comprised ca. 150 days and during this period, the animals reached their final weight of about 35.5 kg. While fattening, the consumption of feed per 1 kg body weight gain of goat kids was determined and the daily body weight gains were calculated from the moment of weaning, i.e. from the 60th day until the slaughter on the 150th day. In the group of goat kids fed the feed supplemented with flax seeds, higher daily body weight gains (211 g/24 h) were obtained compared with the control group (190 g/24 h). The kind of feed the animals were fed impacted the degree of fat accumulation and resulted in the higher per cent content of kidney fat in the group of male goat kids offered the feed mixture supplemented with flax seed (3.10 %) as compared to the control group (2.85 %).