The objective of this study was to determine the effect of hot carcass weight and leanness according to the ‘EUROP’ carcass grading system on the gain of primal cuts obtained from the cutting of carcasses. The investigations were performed in March 2001, on 100 fatteners from the mass population, and originating from a raw meat facility belonging to one meat plant located in central eastern Poland. The carcasses were selected directly on the slaughter line according to the three criteria: leanness assessed using an ‘ULTRA FOM 100’ apparatus manufactured by the Danish company ‘SFK-Technology’, and classified according to the ‘EUROP’ carcass grading system; hot carcass weight ranging from 75.0 to 80.0 kg, as well as from 80.1 to 85.0 kg within each of the ‘EUROP’ grading classes; and gender – from the point of view of the equal number of boars and gilts within each leanness class, as well as within each range of hot carcass weight. It was proved that as the result of raising the hot carcass weight by about 5.0 kg, there was a high gain of meat within the summary increase in meat weight and fat in total in halfcarcass, and that this high gain was particularly clear in Classes from E to O; its level was, respectively: 69% in Class E; 57% in Class U; 93% in Class R; and 89% in Class O. This fact is evidence that there are high reserves referring to the meat tissue deposition process, even in the group of fatteners showing a hot carcass weight of 85 kg, especially in Classes R and O under the EUROP; thus, it is possible to effectively manage and run the process of fattening animals in order to achieve a higher dead weight without decreasing the raw meat quality owing to its adiposity.