Mycoplasma hominis is a commensal organism in the genitourinary tract. Extragenital infections by M. hominis are rare, and its occurrence is usually limited to immunocompromised patients. Here we report two patients with extragenital infection by M. hominis. The first patient, a woman with angioimmunoblastic T cell lymphoma, underwent autologous peripheral blood stem cell transplantation. The second patient, a woman with endometrial cancer, received laparoscopically-assisted vaginal hysterectomy. They both presented with septic symptoms, including fever, and M. hominis was isolated from pleural effusion and ascitic fluid, respectively. We are reporting these two cases of extragenital infection by M. hominis with a literature review to emphasize that the rapid isolation of M. hominis with early treatment can lead to a better prognosis. (Korean J Clin Microbiol 2010;13:47-50)