The yeast vacuolar proton-translocating ATPase is a member of the third class of H(+)-pumping ATPase. A family of this type of H(+)-ATPase is now known to be ubiquitously distributed in eukaryotic vacuo-lysosomal organelles and archaebacteria. Nine VMA genes that are indispensable for expression of the enzyme activity have been cloned and characterized in the yeast Saccharomyces cerevisiae. This review summarizes currently available information on the VMA genes and cell biological functions of the VMA gene products.