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Three species comprise the genus Arctomecon (Papaveraceae). All are endemic to the Mojave Desert region of the southwestern United States. Arctomecon humilis, endemic to Washington County, UT, was listed as an endangered species in 1979 and is presently known from only nine populations. Habitat for this species continues to decline as human development increases. Arctomecon californica is endemic to southern Nevada and the lower Grand Canyon area of Arizona. Arciomecon merriamii is confined to southern Nevada and the Death Valley area of California. Both A. californica and A. merriamii are candidates for listing as threatened or endangered by the U.S. Fish and Wildlife Service. Arctomecon californica populations are seriously threatened by development. We have estimated the variation existing among populations of A. humilis and the degree of genetic similarity this taxon shares with its congeners. Estimates are based on RAPD (randomly amplified polymorphic DNA) analysis of genomic DNA. DNA was extracted from leaf tissue. Tissue from Argemone munita and Rommeya coulterii, proposed close relatives of Arciomecon and Papaver orientale, an outgroup, was also included in the analysis. Results show that little genetic variation exists among the populations of Arctomecon humilis (populations are over 95% similar on average). Populations of A. californica were nearly as similar (similar to 94%). However, A. merriamii populations averaged only about 68 percent similarity. Mean interspecific similarity among the three species of Arctomecon was between 15 and 23 percent. The results provide information on the genetic composition of individual populations that will prove helpful for management decisions. The data also provided insights concerning phylogeny in the family Papaveraceae.