The analysis of the Schizosaccharomyces pombe genome revealed the presence of 14 putative P-type ATPases. The clustering of ATPases resembles that of Saccharomyces cerevisiae, indicating that the main classes of pumps were already present before the split of the Archiascomycetes from the other Ascomycota. The overall amino acid identity between fission and budding yeast P-type ATPases is generally low (30-50%). This is similar to the fungus-plant and fungus-animal comparisons, suggesting that fungal ATPases underwent an extensive process of diversification. Unlike Sac. cerevisiae, fission yeast lacks Na(+)-ATPases, has a single heavy-metal ATPase and three ATPases of unknown specificity. The observed divergence within these fungi might reflect physiological differences, including adaptation to environmental stresses.