Twenty-six polymorphic microsatellite loci were developed for four species of ant-associated root-aphids: Geoica utricularia, Forda marginata, Tetraneura ulmi and Anoecia corni. We found up to 9 alleles per locus, with an average of 4.8. We also report polymorphic cross-amplification of eleven of these markers between different pairs of study species. Furthermore, we tested previously published aphid microsatellites and found one locus developed for Pemphigus bursarius to be polymorphic in G. utricularia. These microsatellite markers will be useful to study the population structure of aphids associated with the ant Lasius flavus and possibly other ants. Such studies are relevant because: 1. L. flavus mounds and their associated flora and fauna are often key components in protected temperate grasslands, and 2. L. flavus and its diverse community of root-aphids provide an interesting model system for studying the long-term stability of mutualistic interactions