Although our understanding of the mechanisms of electrolyte transport across the hepatic plasma membrane is still incomplete, considerable progress is being made. We have attempted in this review to organize what is now known into a descriptive framework, and also to speculate, with an aim toward focusing attention on the potential impact of ion transport in the liver on the regulation of critical hepatic functions, such as cell growth, cell volume maintenance, and bile formation. It is hoped that future investigations will serve to validate or refute these speculations.