A comparative morphological study of Bryobia rubrioculus (Scheuten) from 24 worldwide sites was made to determine whether enough significant variation existed to designate the mites from each location as isolated populations. Forty-seven characters were selected and measured for each mite and analysed using Ward s error sum cluster analysis procedures. These analyses led to the conclusion that B. rubrioculus tends to form distinct populations within each respective location, and mites from locations that do not form clusters are probably a result of automictic parthenogenesis and introductions from other areas. B. rubrioculus was found to be distinct from B. praetiosa Koch [cf. RAE/A 50, p.444] and not part of a large praetiosa complex, and it was confirmed that B. redikorzevi Rekk is a synonym of B. rubrioculus [cf. 57, 481].