Tanacetum isfahanicum Sonboli and Naderifar sp. nov. (Asteraceae-Anthemideae) is described from Isfahan Province, Iran. It is morphologically belonging to T. sect. Xanthoglossa and distinguishing from the closest relative, T. polycephalum, by shape of basal and cauline leaves, shape of capitula, length and width of involucre and color of achene ribs. The phylogenetic position of the new species is reconstructed based on nrDNA ITS sequences variation and its close relationship with T. polycephalum is corroborated.