The nomenclature of the species of rust fungi that occur on species of Myrtaceae is reviewed. Three teleomorph and five anamorph species are accepted. One new combination is made in Physopella, a new species of Uredo is described and a new name is proposed in Uredo. To facilitate identification of the known rust fungi occurring on Myrtaceae, keys are provided to the uredinial and telial taxa. The known hosts of the myrtaceous rusts are recorded. Guava rust, Puccinia psidii, is now known to occur on species in both subfamilies of Myrtaceae, including one of two tribes of the subfamily Psiloxyloideae and seven of the 15 tribes of subfamily Myrtoideae, a total of 20 genera and 71 species. Susceptibility to Puccinia psidii seems to be low among species of Myrtaceae from the Americas but more common among taxa from Asia, Australia and the Pacific.