In order to seek possible confounding factors in relation to clinical responsiveness to high-dose intravenous steroid pulse therapy and orbital irradiation followed by oral steroids in the treatment of thyroid-associated ophthalmopathy (TAO), we reviewed the medical records of 53 admitted patients (22 men and 31 women out of a total pool of 167 patients who had diagnosis of TAO). To assess the improvement TAO, we employed proptosis as an objective index and followed up longitudinally. The final ratios of improvement in the left and right eyes respectively were 71.0% and 64.5%. Significant difference in the therapeutic effect on proptosis was found between male and female at the end of observation. The decrease in proptosis was significantly greater in female patients than in male patients (P<0.05). Among patients' background characteristics, smoking status and body mass index did not relate to the severity of the eye disease but rather to its improvement (right: P=0.18, left: P<0.05). These results suggest that the combined steroid and radiotherapy followed by oral steroid therapy should be optimized to obtain higher effectiveness.