BACKGROUND: The purpose of this study was to examine the incidence of sialadenitis and xerostomia within a year after radioactive iodine administration for thyroid remnant ablation after preparation with recombinant human thyroid-stimulating hormone (rhTSH) or levothyroxine (LT4 ) withdrawal.METHODS: The study has included 121 patients, divided into 4 groups: group A (rhTSH = 100 mCi), group B (rhTSH = 70 mCi), group C (LT4 withdrawal = 100 mCi), and group D (LT4 withdrawal = 70 mCi). Study outcomes were Summated Xerostomia Inventory score and number of sialadenitis episodes after radioactive iodine administration.RESULTS: Salivary gland dysfunction was reported in 31% and 12% of patients, at the end of months 1 and 12, respectively. There was significantly lower incidence in groups A and B in comparison with groups C and D (p = .002 and .021, respectively).CONCLUSION: The use of rhTSH for preparation of radioactive iodine ablation as opposed to LT4 withdrawal reduces the incidence of salivary gland dysfunction. © 2015 Wiley Periodicals, Inc. Head Neck 38: E227-E230, 2016.