Endolymphatic potential is assumed to result from active K transport into the endolymphatic compartment and passive K diffusion in the opposite direction. However, in several in vivo experiments, changes in endolymphatic potential differed from that in endolymphatic K concentration. Moreover, in in vitro experiments, a negative endolymphatic potential was observed in presence of ouabain without K gradient between the two compartments. These observations suggest that the coupling between the K transport and the genesis of the endolymphatic potential is not tight. Several factors may influence separately the endolymphatic potential and the K transport such as the acid-base equilibrium, the integrity of the Reissner's membrane, the hormonal status and the Na transport.