The algae were identified of the Tigris River in Baghdad city for twelve station in the north, center and south of Baghdad city, as 263 algae species were return to 95 genus of seven divisions (Chlorophyta , Cyanophyta , Chrysophyta , Euglenophyta , Bacillariophyta (Diatomata) and Pyrrhophyta), which includes 28 order return to 65 families. The species number of Chlorophyta also reached 58 species return for 31 genus and the species number of Chrysophyta 5 species of 5 genera and the species number of Pyrrhophyta algae 6 species for 5 genera and the species number of Diatomata algae 127 species 32 genus and the species number of Cyanophyta 59 species of 19 genus and the spices number of Euglenales algae of 8 species for 3 genus. Some Chlorophyta dominated in most of the study stations represented by Chlorella vulgaris , Chlorella ellipsoidea, Scenedesmus quadriqadi and Mougeotia scalaris and some of Diatomata represented by Cyclotella meneghiniana, Rhoicosphenia curvata and Coccones placentula and Cymbella tumida and some blue Green algae Chroococcus minor and Oscillatoria limnetica.