The performed investigations evaluated the growth dynamics of Lactobacillus acidophilus DSM 20079, Lactobacillus acidophilus DSM 20242, Bifidobacterium bifidum DSM 20082, Bifidobacterium bifidum DSM 20215, Bifidobacterium bifidum DSM 20239, Bifidobacterium bifidum DSM 20456 in media supplemented with various saccharides, including prebiotic preparations. The addition of saccharides to the medium exerted a significant influence not only on the number of bacterial cells but also on their acid-creating capability. Glucose, lactose and saccharose tumed out to be the easiest available saccharides for all the bacterial strains tested. In the media supplemented with these sugars the highest numbers of bacterial cells were determined. At the shortage of mono- and disaccharides, all strains of the bacteria tested were capable of utilising the prebiotic preparations as sources of carbon and energy in the media. The amount and isomeric forms of lactic acid produced by Lactobacillus acidophilus DSM 20079 and Bifidobacterium bifidum DSM 20239 were determined. Both strains meet the reąuirements adopted by the WHO and produce more than 70% lactic acid L(+) in the media with the addition of various saccharides. Lactobacillus acidophilus DSM 20079 was found to produce significantly higher amount of lactic acid in different media.