Helicobacter (H.) pylori is known to be a bacterial risk factor for gastric cancer. In this study, 16 strains of lactic acid bacteria (LAB) isolated from Mongolian dairy products were screened for potential probiotic activity against H. pylori strain no. 130 in vitro. Lactobacillus (L.) paracasei 06TCa19 and L. plantarum 07MR044 were identified as LAB strains with anti-H. pylori activities. Compared to strain 07MR044, strain 06TCa19 was more potent in reducing H. pylori counts in co-culture. The ability of strain 06TCa19 to inhibit the growth of H. pylori was attributable to its rapid and excessive generation of lactic acid. Moreover, oral administration of strain 06TCa19 was found to significantly reduce the number of colonizing H. pylori in the stomach of H. pylori strain no. 130-infected mice. Thus, strain 06TCa19 is potentially effective against H. pylori infection.