Na^＋/H^＋ exchangers (NHE) are vital transmembrane transporters involved in multiple cellular functions including the regulation of intracellular pH, the control of cell volume and ion transport. Five isoforms of Na^＋/H^＋ exchangers have been cloned and characterized to date; they constitute a new gene family of vertebrate transporters. And these isoforms are highly regulated by a remarkably wide variety of stimuli which can modulate their expression level and activity. Among the isoforms, the increased expression level and activity of human NHE-1 have been found to play a role in some critical diseases, such as tumor, hypertension and diabetes. Thus it may provide a new way of diagnosing and treating for these diseases by investigating on the transcription modulation of NHE-1 gene and the activity regulation of the exchanger.