Foreign bodies in genitourinary tract are common and almost of them are within the bladder. These foreign bodies were inserted or applied for autoerotic, psychiatric, therapeutic, or no definite reasons by the patient. Foreign bodies(a thermometer and a piece of cloth) in the bladder were inserted as a mean of masturbation in two cases, and a cooper wire in the posterior urethra was introduced by iatrogenic causes in one case. In one case, four magnets were inserted into the bladder for the purpose of forceful penile erection. Clinical history, symptom, radiologic study, and endoscopic examination were required to diagnose foreign body. They were easily removed by endoscopic manipulation or open surgical procedure.