Porphyromonas gingivalis seems to perturb the cytokine network to maintain periodontal disease. Although endothelial cells are a leading source of interleukin 8 (IL-8) and monocyte chemotactic protein I (MCP-1), the effect of P. gingivalis on the cells remains unclear. We used reverse transcription-PCR (RT-PCR) to assess levels of IL-8 and MCP-1 mRNA and enzyme-linked immunosorbent assays (ELISA) to evaluate their protein production by human umbilical vein endothelial cells (HUVEC) challenged with P. gingivalis. IL-8 and MCP-1 protein levels decreased in response to challenge with P. gingivalis, and N-a-p-tosyl-L-lysine chloromethylketone (TLCK) prevented the degradation of these chemokines. Furthermore, the bacteria upregulated expression of the mRNAs of these chemokines. Our results indicate that P. gingivalis proteases degraded IL-8 and MCP-1. Degradation of chemokines secreted from endothelial cells may decrease the recruitment of leukocytes and their migration through the endothelium, thus contributing to a delay in the host immune defense mechanism.