Our aim was to evaluate the ability of different strains of Bifidobacteria to cross the gut wall and reach the liver of weaning pigs, and to study the influence of different doses of a probiotic on this parameter. The ability of bacteria to pass from the intestinal lumen to mesenteric lymph nodes and other tissues is called translocation. Several factors promote bacterial translocation, including intestinal bacterial overgrowth, deficiencies in host immune response, and gut barrier damage. Translocation can also be used as a parameter to evaluate a candidate probiotic. Few data are available on the probiotic translocation in weaning pig. We analysed the liver samples from two trials performed with 32 and 64 pigs, respectively, reared from 21 to 35 days of age, fed seven different diets: control diet (C), or C supplemented with one of six different Bifidobacteria strains (1010/CFU/d) (trial 1); or supplemented with four different levels of B. animalis (0, 107, 109, 1011) crossed with 0% or 2% sugar beet fructo-oligosaccharides (trial 2). We found Bifidobacterium spp. genus-specific DNA in liver of subjects from all dietary treatments (control fed pigs included), and no relationship between oral dose and strain appeared. On average 53.1% (trial 1) and 48.4% (trial 2) of the pigs showed the presence of Bifidobacterium spp. genus-specific DNA. We conclude that both endogen and exogenous bacteria can translocate to the liver.