Serum CA 125 is the most useful marker for monitoring patients with epithelial ovarian cancer. However, it can be elevated above normal level in a variety of conditions other than ovarian cancer such as endometriosis, pelvic inflammation disease, and other malignant or nonmalignant disorders, including pulmonary diseases. Recently, we experienced a case of bronchiectasis in which the serum CA 125 level was elevated, changing with the patient's condition. There was no evidence of underlying malignant disease on positron emission tomography or on gynecologic examination, including transvaginal ultrasonography. During follow-up for 14 months, we could not find any clue of malignant disease that could have been the cause of the elevated levels of serum CA 125. Elevated serum CA 125 level should be interpreted carefully according to the patient's clinical condition. In addition, our case suggests that CA 125 may be used as a surrogate marker for acute inflammatory status for chronic pulmonary diseases.