The study compared the nutrient content of selected joints of South African mutton (Class C2) (n = 18) and lamb (Class A2) (n = 18) carcasses of fat code 2 in both classes. South African sheep carcasses are classified according to age by dentition: Lamb carcasses of class A2 show the ruction of no incisors and mutton carcasses of class C2 of more than six incisors. Fatness is assessed by the thickness of subcutaneous fat. Chilled carcass sides were subdivided into the primal cuts. The cuts were dissected into meat (muscle, intermuscular and intramuscular fat), bone and subcutaneous fat (SCF). The soft tissue of the carcass was analysed for selected nutrients. It was found that South African lamb and mutton contain less fat than the nutrient values previously assumed as scientifically correct and presented in the National Food Composition Tables of the Medical Research Council (MRC), USDA. The results from this study emphasize the importance of country specific nutrient data on own food commodities.