This work provides the updatedchecklistof the mayfly (Ephemeroptera) fauna of Iraq;it consists of 30species belonging to 18genera and 10families. The highest number of species belongs to the familiesof Baetidaeand Heptageniidae, whereas the lowest in Ephemeridae, Leptophlebiidae andPalingeniidae that appeared with only one species for each of them.The current investigation is a contribution to the knowledge regarding thebiodiversity of mayflies, with mentioning the synonyms of the species and correcting the scientific names that found in previous publicationsin Iraq.