Presently, little is known about the worldwide genetic structure, diversity, or evolutionary relationships of the white-pineblister-rust fungus, Cronartium ribicola. A collaborative international effort is underway to determine the phylogeographic relationships among Asian, European, and North American sources of C. ribicola and closely related taxa. Here, we present preliminary information on phylogenetic relationships among selected Eurasian and North American populations of C. ribicola using DNA sequences from four nuclear loci totaling over 2,100 bp. Geographic regions included eastern and western North America, northern Germany, Korea, Japan, and northeastern China. Phylogenetic and network analyses suggest C. ribicola comprises at least three distinct clades. Isolates from Korea and China formed one clade, and Japanese isolates formed a second clade that was intermediate the third clade, which comprised isolates from USA and Germany. Identifying the evolutionary relationships and potential origin(s) of C. ribicola that spread through Eurasia and North America, and determining the phylogenetic relationships of its hosts are critical toward understanding this pathogen's native ecology. Such information will help evaluate risks of cryptic introductions, contribute to the development of biological controls, identify sources of host resistance and develop appropriate regulatory practices.