Emerging evidence supports a potential therapeutic role of relaxin in fibrotic diseases including chronic kidney disease. Relaxin is a pleiotropic hormone, best characterized for its role in the reproductive system; however, recent studies have demonstrated a role of relaxin in the cardio-renal system. Both relaxin and its receptor, RXFP1, are expressed in the kidney, and relaxin has been shown to play a role in renal vasodilation, in sodium excretion, and as an anti-fibrotic agent. Together, these findings suggest that the kidney is a target organ of relaxin. Therefore, the purpose of this review is to describe the functional and structural impacts of relaxin treatment on the kidney and to discuss evidence that relaxin prevents disease progression in several experimental models of kidney disease. In addition, this review will present potential mechanisms that are involved in the therapeutic actions of relaxin.