A 10-year-old girl with a 1-year history of lower genitourinary tract symptoms suggestive of bacterial infection but with numerous negative urine cultures was referred to the University of Alabama urology clinic after empirical treatment with multiple antibiotics failed to resolve her symptoms. An extensive urologic evaluation revealed no structural or physiologic abnormalities, but an exudative vaginitis was noted and large numbers of Ureaplasma urealyticum and Mycoplasma hominis were isolated from the lower genital tract. Cultures for Chlamydia, viruses, and routine bacterial pathogens were negative. After initiation of tetracycline therapy, symptoms resolved and subsequent cultures for mycoplasmas were negative. In addition, a seroconversion was noted for M hominis but not for U urealyticum. Chlamydia serology was negative. It was later learned that the patient had been sexually molested just prior to the onset of symptoms. This case illustrates the necessity of early consideration of a mycoplasmal etiology in the patient with persistent genitourinary symptoms and no obvious bacterial pathogen, or in the patient whose condition is refractory to routine antibiotic therapy.