Technical Abstract: We characterized patterns of genetic variation in populations of the invasive fire ant Solenopsis invicta in China using both mitochondrial DNA sequences and nuclear DNA microsatellites. All study samples, which were collected from 17 sites across the current infested range in China, were assigned to one of three distinct genetic clusters, consistent with the hypothesis that there were at least three independent invasions of S. invicta into China. Most colonies from spatially distant, outlying areas are genetically similar to one another and appear to share a common source (Wuchuan, Guangdong province), suggesting that long-distance jump dispersal has been a prevalent means of recent spread of fire ants in China. Furthermore, most colonies at outlier sites are of the polygyne social form (featuring multiple egg-laying queens per nest), reinforcing the important role of this social form in subsequent range expansion following initial invasion. Several analyses reveal characteristic signatures of genetic bottlenecks for S. invicta populations in China. The major findings of this study (i.e., multiple introductions, long range dispersal, and genetic bottlenecks) are consistent with those of earlier investigations of other invasive fire ant populations.