Fluctuating asymmetries (FA) are small stress-induced random deviations from perfect symmetry that arise during the development of bilaterally symmetrical traits. One of the factors that can reduce developmental stability of the individuals and cause FA at a population level is the loss of genetic variation. Populations of founding colonists frequently have lower genetic variation than their ancestral populations that could be reflected in a higher level of FA. The European starling ( Sturnus vulgaris ) is native to Eurasia and has been introduced successfully in USA in 1890 and Argentina in 1983. In this study, we documented the genetic diversity and FA of starlings from England (ancestral population), USA (primary introduction) and Argentina (secondary introduction). We predicted the Argentinean starlings to have the highest level of FA and lowest genetic diversity of the three populations. We captured wild adult European starlings in England, USA, and Argentina and allowed them to molt under standardized conditions, to evaluate their FA of primary feathers and their mtDNA diversity. For genetic analyses, we extracted DNA from blood samples of individuals from Argentina and USA and from feather samples from individuals from England and sequenced the m itochondrial control region. Argentinean starlings showed the higher composite FA and exhibited the lowest haplotype and nucleotide diversity from all populations studied . USA population showed a level of FA and genetic diversity similar to England population. Therefore, the level of asymmetry and genetic diversity found among these populations was consistent with our predictions based on their invasion history.