The research material comprised 167 young bulls of Black and White variety of Holstein-Friesian breed, which were fed feed doses containing a high per cent amount of nutritive feed with hay and straw added. The experimental fattening was performed till the young bulls had a weight of about 570 kg. Despite the intense feeding of the young bulls analyzed and despite the daily increases of more than 1 kg in their weight, their carcasses were classified, under the EUROP system, into the R class (22.75 %) and into the O class (77.25 %); as for their fatness, they were classified into Class 1 (11.38 %), Class 2 (58.69 %), and Class 3 (29.94 %). The young bulls with carcasses classified into the R class were characterized by higher mean values of their body weight after the completed fattening, their pre-slaughter weight, their hot carcass weight, and also by a 1.2 % higher mean value of the slaughter yield indicator. On the other hand, the young bulls with carcasses classified into the Fatness Class 1 had lower daily increases in their body weight, a lower pre-slaughter body weight, a lower post-slaughter carcass weight, and a lower indicator of their slaughter yield. The research performed proved a high fluctuation in the mean values of slaughter yield indicator of young bulls, as well as a positive and statistically significant correlation existing between their slaughter yield and their carcass weight, and a negative correlation between this yield and the pre-slaughter weight.