In the present work, the survival of two commercial strains of probiotic bacteria: Bifidobacterium animalis subsp. lactis BB-12 and Lactobacillus acidophilus LA-5, and their influence on the composition, proteolysis and sensory characteristics of soft sheep cheese were studied. Three different types of cheeses were made: control cheese (QT) without addition of probiotic bacteria, and two experimental cheeses with addition of BB-12 (QBb) and LA-5 (QLA). Gross composition, pH, counts of starter and probiotic bacteria and proteolysis were evaluated during ripening at 4, 15 and 30 days, and a descriptive sensory analysis was conducted at the end of ripening (30 d). The initial pH in all cheeses was 5.15±0.02 and was slightly increased at 30 days at a value of 5.31 ± 0.02; pH values were similar in all cheeses. Gross composition was similar between control and probiotic cheeses; mean values of moisture and content of fat and protein (expressed in dry matter) were 47.61±0.8 (%w/w), 53.38±1.52 (%w/w) and 42.87±1.15 (%w/w) respectively. The counts of BB-12 and LA-5 in the curd were ~108 CFU/g and were maintained at this level in the cheeses during all ripening time. The addition of BB-12 and LA-5 produced an increase in the levels of secondary proteolysis, being the effect more marked for LA-5. The descriptive sensory analysis of cheeses showed that the addition of LA-5 and BB-12 did not produce defects in flavor and taste but rather significantly improved (p < 0.05) the elasticity, appearance of mass and mouthfeel of cheeses. Soft sheep cheese demonstrated to be a suitable carrier for these probiotic cultures, and the characteristics of these cheeses were slightly improved by the addition of probiotic bacteria. © All Rights Reserved.