AIM: To determine the clinical characteristics of a prospective study of patients with Graves' ophthalmopathy(GO). · METHODS: We reviewed clinical manifestations, and medical records of 103 patients in whom GO was diagnosed between 2003 and 2005. · RESULTS: Among 103 patients with GO, 48 (46.6%) male and 55 (53.3%) female, with mean age of 45 (range; 18-73) years, 95 (92.2%) patients had Graves' hyperthyroidism, 3 (2.9%) had primary hypothyroidism, and 5 (4.8%) were euthyroid. The mean duration of ocular symptoms was 13.2 (range 2-95) months while the mean duration of dysthyroid symptoms was 39.4 (range 6-180) months. Unilaterality occurred in 12 patients. Eyelid retraction was presented in 90 patients (87%), whereas the approximate frequency of exophthalmos was 77.6% (80 patients); restrictive extraocular myopathy, 29% (30 patients); evidence of extraocular enlargement on CT-scan in 52 patients of 70 patients (74%) that was evaluated, and optic nerve dysfunction, 5.8% (6 patients). 22 (21%) patients had glaucoma associated with GO that 7 (6.7%) of them were normal-tension glaucoma. · CONCLUSION: Eyelid retraction was the most common clinical sign of GO in our patients. Larger prospective studies are suggested to evaluate both the prevalence and possible racial difference in its clinical presentation in Iranian population.