Five widely documented mechanisms of chloride transport across plasma membranes are anion‐coupled antiport, sodium and hydrogen‐coupled symport, Cl– channels, and an electrochemical coupling process. No genetic evidence has yet been provided for primary active chloride transport despite numerous reports of cellular Cl–‐stimulated ATPases co‐existing, in the same tissue, with uphill chloride transport that could not be accounted for by the five common chloride transport processes. Cl–‐stimulated ATPase activity is a common property of practically all biological cells with the major location being of mitochondrial origin. It also appears that plasma membranes are sites of Cl–‐stimulated ATPase activity. Recent studies of Cl–‐stimulated ATPase activity and active chloride transport in the same membrane system, including liposomes, suggest a medication by the ATPase in net movement of chloride up its electrochemical gradient across plasma membranes. Further studies, especially from a molecular biological perspective, are required to confirm a direct transport role to plasma membrane‐localized Cl–‐stimulated ATPases. J. Exp. Zool. 289:215–223, 2001. © 2001 Wiley‐Liss, Inc.