The diversity and distribution of the rotifers family Notommatidae was studied in the northwest, the south and the southwest of Iran. In total, 29 species were identified, of which, 25 are new records for the country. New records include the following species: Cephalodella forficata, C. cf. mus, C. vittata, C. ventripes, C. lepida, C. inquilina, C. gibboides, C. tincaformis , C. obvia, C. sterea, C. physalis, C. gracilis, Eosphora najas, E. Ehrenberg, E. therina, E. anthadis, Eothina elongate, Monommata actices, Notommata pygma, N. glyphura, N. diasema, N. brachyota, Resticula nyssa, R. melandocusa and Pleurotrocha atlantica. Spatial and temporal patterns of the species diversity were evaluated. Descriptions are provided for all the identified species in detail. Biogeography and environmental conditions favorable for identified species were referred. A great richness of rotifers in aquatic environments is generally found in regions where vegetation predominates, either in aquatic or in the ecotone zone between aquatic and terrestrial environments
