Cheese has been shown to be an appropriate carrier for selected strains of probiotics. The functionality ofprobiotics in cheese has, however, been less investigated. A model simulating the human gastrointestinal tract showed thatL. acidophilus NCFM and L. rhamnosus HN001 in Gouda cheese survived passage through the upper gastrointestinal tract.Furthermore, the amount of total lactobacilli, L. acidophilus, and L. rhamnosus increased significantly in the colonicfermentation simulations, compared to the non-probiotic control cheese. A human feeding trial showed that consumptionof probiotic cheese (15 g, 109 CFU/day) increased both natural killer cell activity and phagocytic activity. The results showthat cheese is an appropriate carrier for probiotics and maintains their functionality.