The present study shows the chromosome numbers of Tanacetum parthenium with 14 populations and eight populations both in Hamedan Province, Iran. In this study, the two species showed intraspecific polyploidy. Among the populations of T. parthenium studied eight populations showed the chromosome number of 2n=2x=18, while five populations showed 2n=4x=36, that confirmed the previous results. Additionally, a population showed the hexaploid chromosome number of 2n=6x=54. According to the documentation of the chromosome numbers of Tanacetum, the present count of hexaploid was the very first recording for T. parthenium. In all populations the basic chromosome number was x=9. Also in this study, mitotic chromosome number for eight populations of Tanacetum polycephalum were reported; in two populations of this species showed the chromosome number of 2n=4x=36 and six populations confirmed the previous count of , chromosome number was 2n=4x=36. six populations confirmed the previous count of n=6x=54.