The oral bacterium Porphyromonas gingivalis is one of the key-pathogens causing the inflammatory disease periodontitis, as well as being associated with the progression of atherosclerosis. The bacterium has different virulence factors that induce an inflammation, including production of cytokines and chemokines, which has a role in both diseases. The proteases, called gingipains, are one important group of virulence factors that for example degrade host proteins, causing tissue damage. The aim of this study is to investigate whether viable P. gingivalis affects fibroblasts’ viability and modulate the associated immuno-regulatory mechanisms. The fibroblasts were therefore stimulated with the bacteria and the viability and interleukin (IL)-8 production were measured. The morphology was also studied using microscopy. We found that P. gingivalis adheres to fibroblasts, which survives and proliferate even at high concentrations of bacteria over time. In addition viable bacteria induce a production of IL-8, however the chemokine is probably degraded by the gingipains at high concentrations of bacteria. In conclusion, P. gingivalis adheres to fibroblasts, stimulate fibroblast proliferation, and trigger the release of IL-8, which is then decreased, possibly due to the catalytic activity of the gingipains.