Carcass, meat quality and muscle fibre traits of m. longissimus lumborum were studied in 61 Zlotnicka Spotted (ZS) pigs and 35 commercial crossbred (Polish Large White x Polish Landrace) pigs. The animals received organic feed ad libitum and were slaughtered at 210 days of age. The current findings indicate that both slaughter weight and cold carcass weight were significantly lower, and backfat thickness higher for ZS pigs compared to commercial pigs, while the commercial pigs exhibited longer carcasses and greater area, height and width of the loin eye. No significant differences were found in IMF content between the analysed groups. Moreover, the percentage of type I fibres was higher and their diameter was larger in m. longissimus lumborum of ZS compared to commercial pigs, whereas the opposite occurred for type IIB fibre percentage and diameter, and that concurred with markedly higher pigment content and higher pH(u), redness (a*), plasticity values, and significantly lower drip loss, WHC--loose water, and colour lightness (L*) values in ZS pigs than those found in commercial pigs. Also, sensory assessment of raw meat confirmed that m. longissimus lumborum of ZS pigs was characterized by more favourable colour and less exudative meat.