We describe the isolation and development of 14 polymorphic microsatellite loci for the critically endangered plant-louse Trioza barrettae (Hemiptera:Triozidae). The loci were tested in 25 individuals from a single population situated in the south-west of Western Australia. No evidence of linkage disequilibrium was detected between any pair of loci. However, eight loci showed significant departures from Hardy-Weinberg expectations. The number of alleles per locus ranged from 2 to 27.