Trichomonas vaginalis is an extracellular protozoan parasite that binds to the epithelium of the human urogenital tract during infection, and causes contact-dependent cytotoxicity. Neutrophils, macrophages and mast cells known to be involved in innate immunity produced proinflammatory cytokines by stimulation with T. vaginalis. Crosstalk between vaginal epithelial cells (VEC) infected with T. vaginalis and mast cells showed increased inflammatory response compared with that by VECs only. In addition, we confirmed that T. vaginalis caused prostatitis in rat by injection via urethra, and prostate epithelial and stromal cells reacted with trichomonads produced cytokines, including interleukin-1β, CXCL8, and CCL2, resulting in increased migration of neutrophils and monocytes. In further study, we will investigate the role of crosstalk between prostate cells infected with T. vaginalis and inflammatory cells on prostatic cell proliferation or prostatic cancerous change. However, it has not yet been determined whether prostate cancer is associated with T. vaginalis infection. In order to determine their association, a serologic test showing high sensitivity and specificity is necessary. In addition, a molecular diagnostic test with improved sensitivity should be developed for early detection and treatment of trichomoniasis.