Law RH, Quan DL, Stefan AJ, et al. - In the current study, the largest cohort of patients treated for primary hyperparathyroidism (PHPT) with a history of radioactive iodine (RAI) exposure was reported and the disease characteristics were assessed. Comparison of patients, with and without a history of RAI treatment, who underwent surgery for PHPT was done in this retrospective analysis. Among 469 patients, 28 had a history of RAI treatment, all for Graves' disease. The manner of approaching PHPT in patients with a history of RAI treatment can be the same as in RAI naive PHPT patients; however, the risk of recurrence of PHPT may be higher in RAI exposed patients.