The investigations were performed on 286 pig carcasses received from different sources: a raw meat facility belonging to the ‘Meat Factory’ at Morliny near Ostróda (62 carcasses), ‘Łmeat’ Company at Łuków (93 carcasses), and ‘Prime Food’ Company at Przechlewo (131 carcasses). In the paper, the thickness of fat and of the LD muscle was determined using 2 types of equipment: I – Sydel CGM and SFK Ultra-Fom 300; II – slide caliper. It was proved that, irrespective of the place where measurements were taken and of the carcass mass, the mean thickness of fat measured using the slide caliper was by 2 mm higher than the fat thickness measured using the ‘CGM’ optical-needle device. However, when measuring the thickness of LD muscle, inverse  correlations were obtained since the values measured were by about 2 mm lower compared with the measurements taken using the slide caliper. The correlation factors between the fat thickness values measured by the slide caliper and those measured by the ‘CGM’ apparatus were high, and ranged from r = 0,90 to r = 0,94. As for the values of LD muscle thickness measured, the correlation factors were lower, and ranged from r = 0,63 to r = 0,78. On the basis of the fat thickness values measured by the slide calliper and the ‘Ultra-Fom 300’ apparatus, it was evident that the mean thickness of fat was by about 1 mm higher if the ‘Ultra-Fom 300’ apparatus was used. Then again, inverse correlations were obtained when measuring the thickness of the LD muscle, since the results of measurements taken by the slide calliper were by about 5mm higher. The correlation factors between the fat thickness values measured by the slide caliper and those measured by the ‘Ultra-Fom 300’ apparatus were high, and ranged from r = 0,88 to r = 0,92. In the case of the LD muscle thickness measured, the values of correlation factors were lower and, ranged from r = 0,50 to r = 0,66.