A comparative morphological study of Bryobia rubrioculus {Scheuten} from 24 worldwide sites was made to determine if enough significant variation existed to designate the mites from each locale as an isolated population. Forty-seven characters were then selected and measured for each mite and analyzed with Ward's error sum cluster analysis procedures. These analyses led to the conclusion that: {1} B. rubrioculus tends to form distinct populations within each respective locale, and mites from locales that did not form clusters are possibly a result of automictic parthenogenesis and introductions from other areas; {2} B. rubrioculus is distinctly separate from Bryobia praetiosa {Koch} and not part of a large "praetiosa" complex; {3} mites from the U.S.S.R. are not Bryobia redikorzevi Reck, but, instead, are B. rubrioculus; and {4} some of the characters used in earlier classifications of B. rubrioculus are excellent.