Probiotics have been used for about a century as natural components in supplements and functional foods, mainly in milk drinks and yogurts. Selected probiotic strains have also been included into cheese which has been shown to be an appropriate carrier for probiotics and can deliver them in sufficient numbers. The food matrix in which probiotics are ingested may affect the survival in the intestine. Since survival is considered as a precondition for the beneficial effects of probiotics, in a recent study the survival and amount of probiotics in cheese were investigated by using models simulating the human gastrointestinal tract, after which an intervention study was performed. Gouda cheese with and without probiotic strains (Lactobacillus rhamnosus HN001 and L. acidophilus NCFM®) was first analysed in vitro. The cheese was digested, before it was tested in a human colon simulator. The in vitro simulation showed that the probiotics in the cheese survived the simulated passage through the upper gastrointestinal tract, and that the amount of total lactobacilli, L. acidophilus, and L. rhamnosus increased significantly in the colonic fermentation simulations of the probiotic cheese, compared to the nonprobiotic control cheese. A subsequent human intervention study showed that consumption of probiotic cheese (15 g, 109 cfu/day) increased both natural killer cell activity and phagocytic activity. This confirms earlier observations with L. rhamnosus HN001 in reconstituted fat-free milk, indicating that cheese can be an appropriate carrier for probiotics.