Tamarix L. with almost 54 species is the largest genus of the Tamaricaceae. This study was carried out on the species of Tamarix that growing in Iran. Internal transcribed spacer (ITS) sequences were obtained for 15 samples recognized by recent taxonomic treatments from Iran. In addition, we used 19 previously ITS sequences from Gen Bank to test the monophyly of Tamarix in Iran. Phylogenetic analysis were conducted using Bayesian inference. In this study we use DNA sequence data to identify species of Tamarix that growing in Iran, and to determine if the molecular data are congruent with the morphological distinctions that currently segregate taxa. We also test congruence of morphologically based sectional classifications and our molecular gene trees. The results indicate that Tamarix species from Iran constituted a monophyletic group. Data analysis indicates the three taxonomic sections based on morphology (Baum 1978) are not supported by the molecular analyses as well as the classification of species according to androecial disc morphology so not true but leaf morphology and number of floral parts are useful for the taxonomy of Tamarix species. To determine the evolution of Tamarix use of morphological characteristics coupled with molecular data will be most effective.