Steers, in comparison with bulls, grow slower and poorer covert feed, but their meat contains more intramuscular fat and its colour is lighter; it is more tender and characterized by a higher water-holding capacity. The objective of this research study was to determine the effect of fattening system and age at slaughter on the slaughter value of 46 crossbred beef steers produced by mating Polish Holstein-Friesian cows with Limousine bulls. The steers were fattened intensively to the age of 15 or 18 months, and semiintensively to the age of 18 or 21 months. The most valuable carcasses were produced from steers fattened intensively to the age of 18 months. They were characterized by the highest weight (321.1 kg), the best conformation (R class in the EUROP system), and the highest weight of their five most valuable cuts (104.69 kg). The meat of those animals had the highest intramuscular fat content (4.71%), and this fact meets the changing preferences of consumers. In addition, it was proved that the fattening of the steers to the age of 21 months was associated with an increase in the carcass fatness and with a significant decrease in the per cent content of the most valuable cuts from carcass.