Lithium has been used as the gold standard in the treatment of bipolar disorders for decades. Because of its narrow therapeutic range, lithium toxicity is a usual clinical problem. Long-term lithium therapy also comes at the cost of severe renal side effects, including nephrogenic diabetes insipidus and, rarely, end-stage renal disease. In this article, the pathologic mechanisms of lithium in the kidney will be reviewed, and the clinical manifestations of poisoning, different types of therapy, and the indications for hemodialysis are introduced.