Abstract <p>The research study was carried out to improve the meat and wool production and performance of lambs of the Southern Meat sheep breed through crossing with the Ile de France rams. The research involved 180 Southern Meat ewes sampled for the experiment. They were divided into two groups with the analog principle, considering their age, wool clip, and liveweight. The ewes of the first group were mated by the Southern Meat rams, while the second-group ewes were mated by the Ile de France rams. The daily liveweight gain in the 4–6-month-old and 6–8.5-month-old crossbred progeny, compared to the purebred ram lambs, increased by 17.2 and 28.6%, respectively. The experimental test slaughter results for the 8.5-month-old ram lambs showed that the Il de France half-bred ram lambs had heavier slaughter weight of carcasses (by 21.4%) with 55.4% slaughter yield. In addition, the meat weight of those ram lambs was greater than that in the purebred animals by 4.49 kg, or 29.8%. The ratio of meat + fat to bones increased from 2.99 in the purebred lambs to 3.75 in the crossbred animals, or by 25.4%. The dry matter and protein contents in the mean test sample of crossbred animal meat comprised 30.05 and 19.38%, respectively, while they made up 29.58 and 18.99% for the purebred animals. The alkaline phosphatase concentration in the crossbred animal blood was 43.5 IU/L, or 30.5% higher than that for the purebred animals. The energy contents in the cross- and purebred animal meat comprised 8.25 MJ and 8.12 MJ, respectively. The dry matter intake per 1 kg liveweight gain in the 4–6-month-old Southern Meat ram lambs crossbred with the Il de France was lower than that for the purebred animals by 0.57 kg, or 9.1%. With respect to the exchange energy and raw protein, they were lower by 0.51 FEU, or 7.3%, and 102 g, or 10.1%, respectively. The differences in the parameter values increased with age, reaching 13.7, 13.8, and 16.4% to the age of 6–8.5 months, respectively.</p>