Although thiazide diuretics are frequently recommended as the first-line anti-hypertensive according to the practice guidelines and results of the major clinical trials such as the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT)16-18), the mechanism and optimal treatment of thiaizde-induced hyponatremia (TIH) remain unclear. In this review, we will explore the pathogenesis, discuss the clinical features, and suggest an approach to the treatment of TIH.