Ceroplastes sinensis Del Guercio is a pest of commercial citrus in Australia and has been recorded from New Zealand, southern Europe, northern Africa, North America and Mexico. Its distribution is mainly temperate and it is more restricted climatically than previously believed. Uncertainty concerning the place of origin of C. sinensis has thwarted previous attempts at biological control. In the present study, a novel and cost-effective approach using cladistic estimates is demonstrated to determine the place of its origin. Cladistically derived phylogenies are commonplace for many organisms, but the method has not been used before to predict the area of origin of a cosmopolitan pest. Cladistic analysis of the wax scales predicts a native range for C. sinensis within Central or South America. This prediction appears to have been confirmed by the recent discovery of heavily parasitized individuals of C. sinensis in Argentina. The cladistic analysis also allows prediction of the geographical origin of three other widespread wax scale speries:Ceroplastes ceriferus (Fabricius) may be of Neotropical origin, C. rubens Maskell and C. rusci (Linnaeus) are probably native to the Afrotropical region. The approach used has wide implications because the native areas of many other economically important pests are still unknown or uncertain.