Genetic variation of Michigan elk is examined by use of protein electrophoresis on cellulose acetate. Six western elk populations (Cervus elaphus nelsoni, Rocky Mountain elk) are surveyed and contrasted with Michigan elk. Significant differences in allele frequencies (χ2 = 227.20, d.f. = 28, P < 0.001) and moderate genetic variation exists among the elk herds examined (mean FST = 0.100). However, no significant differences in allele frequencies and small genetic variation are found among the three populations in or near Yellowstone National Park (total χ2 = 6.360, d.f. = 4, P = 0.174; mean FST = 0.034). Moreover, no significant differences are found when the reintroduced populations of Vermejo Park, New Mexico, and Wichita Mountains, Oklahoma, are included with the three populations from the Yellowstone area (total χ2 = 15.131, d.f. = 12, P = 0.234; mean Fsx= 0.038). Significant differences in allele frequencies and moderate genetic variation exist among the elk populations when either or both of the reintroduced populations of Michigan or Mt. Taylor, New Mexico, are added to the analysis of the five other elk populations. Michigan elk have a unique PGM-1 allele not shared by any of the other elk populations examined, but the unique allele is likely to be homologous to alleles among Roosevelt elk known from previous studies. The claim that the Michigan elk herd descends from seven individuals from Yellowstone National Park or the National Elk Refuge is not supported by historic or genetic evidence.