Trichomona vaginalis infection is a sexual transmitted disease that affects human fertility. In men, trichomoniasis has been related to infertility by deficit of sperm cell quality and function due to physical damage. In women, trichomoniasis has been related to infertility due to pelvic inflammatory disease that compromises tubal patency. In this article, a case of unexplained infertility in a couple that was undergoing IVF treatment is discussed. Semen sample analysis demonstrated the presence of Trichomona vaginalis, polymorphonuclear cells, and asthenozoospermia. A protocol for separation and capacitation of optimal motile sperm needed for IVF procedure was utilized and a capacitated sperm sample with complete removal of trichomonas and polymorphonuclear cells was obtained. Capacitated motile sperm were used to achieve IVF fertilization and embryo development and the embryo obtained was transferred into the uterus. However, embryo implantation failed and pregnancy was not achieved, probably as a consequence of trichomoniasis in the asymptomatic female partner. The result indicates that Trichomona vaginalis pathogenicity, adverse reproductive health outcomes, in time diagnosis, and treatment may improve implantation rate in patients with unexplained infertility undergoing ART.