Testicular inflammation is classically observed in pathogenesis caused by infectious agents, environmental toxins, trauma, or autoimmune reactions and can lead to transitory or even permanent sterility. In these situations, a leukocyte infiltration is generally encountered. Macrophage inflammatory proteins (MIP)-1α and −1β and monocyte chemoattractant protein-1 (MCP-1) are CC-chemokines involved in macrophage and lymphocyte chemoattraction. In the present study, using reverse transcription-polymerase chain reaction, Northern blot, and a specific ELISA, we investigated whether or not these chemokines are present within the testis and whether they are induced by a number of proinflammatory cytokines and lipopolysaccharides (LPS). MIP-1α and MIP-1β were not detected in Sertoli cells, germ cells, peritubular cells, or Leydig cells. In contrast, MCP-1 mRNA and protein were found to be expressed by control isolated peritubular cells, and expression was markedly stimulated by interleukin-1α and−1β (IL-1α and IL-1β), tumor necrosis factor α (TNF-α), interferon γ, and LPS. Leydig cells expressed MCP-1 when stimulated by IL-1β. In contrast, MCP-1 was not found to be produced by Sertoli cells or germ cells as established by Northern blot and ELISA techniques. The kinetics of MCP-1 production by peritubular cells, as demonstrated by expression as early as 8 h poststimulation, are compatible with there being a rapid mobilization of these cells and this chemokine in an inflammatory process. Moreover, MCP-1 production by peritubular cells after half-maximal stimulation by LPS, TNF-α, and IL-1β (2 pg/ml–0.9 ng/ml) is also compatible with the physiologic concentrations of the proinflammatory cytokines generally found in an inflammatory site. It is concluded that MCP-1 is produced by Leydig cells and peritubular cells and that it could be involved in the mobilization and migration of leukocytes observed during testicular inflammation.