In this paper, the effect of probiotic rods: Lactobacillus casei, Lactobacillus acidophilus, and Bifidobacterium lactis on the content of CLA in the model ripening cheeses was determined. During the ripening period of cheeses, the count of living cells of the micro-organisms studied was determined, too. The model cheeses produced were characterized by a fat content amounting to over 23% in dry mass and by a water content of about 58%; thus, they were categorized as semi-fat, soft cheeses. In all the samples of fresh cheeses, the content of CLA was about 700 mg per 100 g fat. In the cheeses ripening at a temperature of 6°C during a period of 8 weeks, the count of living probiotic cells remained at the same level of 10⁷–10⁸ CFU/g and met the requirement of therapeutic minimum. Under the ripening conditions applied, no effect of the selected probiotic bacteria on the CLA content in the model ripening cheeses was found.