Background: The species of dermatophytes have been identified and classified by morphological and biochemical characterization as well as by mating experiments. But these techniques are either time consuming or lacking specificity. Recently molecular analysis has been introduced to the field of medical mycology. Objective: We investigated the phylogeny and taxonomy of the dermatophytes using sequence analysis of the ribosomal intemal transcribed spacer 1 (ITS1) region. Methods: 15 species of dermatophytes (6 strains of T. rubrum, 4 strains of T. meetagrophytes subtypes, M. canis, M. gypseum, E. floccosum, T. verrucosum, and T. tonsurans) were cultured on Sabouraud dextrose broth and their DNA was extracted by bead-beating method. Cloning and sequencing of PCR product was done. Results: The size of specific bancls among dermatophytes was 340 bp in ITS1 region. Phylogenetic analysis of sequences reveaied that 6 strains of T. rubrum showed genetically identical patterns in intraspecies, but subtypes of T. mentagrophytes were different. The other dermatophytes showed different patterns in interspecies. The following taxonomy were so closely related: granular form of T. mentagrophytes and T. tonsurans; powdery form, persicolor form and downy form of T. mentagrophytes; and M. gypseum and E. floccosum. Conclusion: The phylogenetic analysis of ITS1 region provided useful information for classification and understanding the evolution of dermatophytes species.