The kidney is capable of regeneration. In response to a variety of insults, renal epithelial tubular cells dedifferentiate into an immature phenotype, proliferate, migrate to the injured area, and redifferentiate into mature polarized epithelial cells. In animal models of acute kidney injury induced by renal ischemia or renal toxins, various growth factors, transcription factors, chemokines, and extracellular matrix components have been demonstrated to be involved in the regeneration process. Recent research has suggested the existence of renal stem/progenitor cells in the kidney and their involvement in renal regeneration. In this review, we will focus on the mechanisms of tubular regeneration after kidney injury, particularly on label-retaining cells actively engaged in this process, and discuss their potential as targets of regenerative therapy for various kidney diseases.