The purpose of this study was to systematically provide a database for estimating radiation dose of individuals nearby (131)I-treated hyperthyroid patients. External dose rates were measured on 48 hyperthyroid patients using a survey meter in front of patients' thyroid glands. The initial measurement was recorded within 30 min post radioiodine administration at 0.3 m, 0.6 m, 1 m, and 2 m. Follow-up measurements were carried out up to 12 d post radioiodine administration. In addition, ambient dose rates of different locations such as wards, patients' washrooms, medical staffs' workplaces, and corridors were also measured. The Na131I treatment dose administered in this study ranged from 74-555 MBq. Significant positive correlation between dose rate at 1 m and the administered dose was found in this study. The normalized external dose rates at 0.3 m were 0.234 µSv h(-1) MBq(-1) at 0.5 h, 0.325 µSv h(-1) MBq(-1) at 4 h, 0.308 µSv h(-1) MBq(-1) at 6 h, 0.301 µSv h(-1) MBq(-1) at 24 h, 0.259 µSv h(-1) MBq(-1) at 48 h, 0.234 µSv h(-1) MBq(-1) at 72 h, 0.224 µSv h(-1) MBq(-1) at 96 h, 0.186 µSv h(-1) MBq(-1) at 120 h, and 0.158 µSv h(-1) MBq(-1) at 144 h, respectively. With these results, the authors estimated radioactive radiation dose for the public and medical staffs near (131)I-treated hyperthyroid patients. This study is beneficial for radiation safety decision-making.