Mycoplasma hominis, a commensal organism that is potentially pathogenic both in maternal perinatal and in neonatal infections, also causes nongenitourinary infections in adults. We reviewed the clinical features of cases from the literature and emphasized recent cases. Infection sites were classified as blood, vascular sites, wounds, central nervous system, joints, and respiratory tract. Twenty-one of 31 newly summarized cases and 32 of 67 overall cases were associated with immunosuppression and/or hypogammaglobulinemia. Clinical suspicion, use of appropriate culture media, and determinations of gamma-globulin levels and of antibodies specific to Mycoplasma are indicated in the proper clinical setting. These types of M. hominis infection appear to be linked to suppressed cell-mediated immunity and/or hypogammaglobulinemia.