Dexmedetomidine-related polyuria has been observed in animal experimental studies, while only limited cases have been reported in humans. Thus, this rare effect is not well recognized. Herein, we report the case of a 26-year-old man who underwent total thyroidectomy and experienced intraoperative dexmedetomidine-related polyuria, which was subsequently resolved using pituitrin. Moreover, we review the current literature on dexmedetomidine-related polyuria and analyze the potential mechanisms of this rare effect.