Hearing loss (deafness) affects approximately 250 million people globally. The major cause of deafness is loss of hair cells and spiral ganglion neurons due to aging, antibiotic use, noise exposure, and genetic defects. At the present time, there is no effective method for restoration of hearing biologically. Cochlear stem cells/progenitors (CSCs), quiescent in the organ of Corti, are excellent candidates for restoration of cell types in the organ of Corti biologically. However, little is known about the biology of CSCs and developmental cues for CSCs to differentiate into hair cells and neurons at the present time. In this article, we briefly reviewed the isolation of CSCs from the postnatal organ of Corti in mice and their capability to differentiate into hair cells and neurons in vitro under the guidance of a group of growth factors: sonic hedgehog (SHH), epidermal growth factor (EGF), retinoic acid (RA), and brain-derived neurotrophic factor (BDNF), herein termed SERB. The identification of CSCs and their differentiation signals is potentially of clinical importance.