Urinary symptoms and urodynamic studies were evaluated prospectively in 33 women undergoing radiation therapy for cervical cancer. Patients were evaluated during treatment, after one to two months, and after five to six months. Significant reductions in peak urinary flow, volume at first desire to void, cystometric capacity, and bladder compliance were evident during and immediately after therapy. Bladder symptoms and urodynamic alteration did not correlate with age, race, or stage of disease. Bladder compliance was significantly reduced in those patients receiving more than 3000 rads to the entire bladder from external beam irradiation. © 1987 by The American College of Obstetricians and Gynecologists.