The Na+/H+ antiporters play a primary role in the maintenance of intracellular pH homeostasis and dynamic balance of cellular Na+, and in the regulation of cell volume. Currently, many Na+/H+ antiporter genes involved in the resistance to high salt and alkaline pH stresses have been identified and functionally characterized in various bacteria. The prospection for novel Na+/H+ antiporters from unexplored habitats, in conjunction with our understanding of the mechanisms responsible for Na+/H+ antiport activity, will provide new insights into industrial and agricultural biotechnology. In this review, we chose four physiologically distinct bacteria as examples, and summarized the classification, structure and function of bacterial Na+/H+ antiporters.