Because insect fat bodies are known to contribute most of the hemolymph proteins, the effects of fat body intracellular parasitism by the microsporidia Thelohania solenopsae on fire ant hemolymph proteins were investigated.  Protein profiles were compared between infected and uninfected fire ant alates and dealates (both inseminated and uninseminated) using sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) at 10% acrylamide and subsequently stained by silver.  Uninfected dealated (both inseminated and uninseminated) queens from infected colonies were also compared.  In the case of inseminated, dealated queens, several protein bands were found to be down – regulated in the infected queens; while other protein bands were found to be up-regulated in the control queens from uninfected colonies.  In the case of uninseminated dealates, protein bands were also observed to be down-regulated in infected queens.  In the case of alated queens, several protein bands are found to be down regulated in the case of infected queens as well.  These results suggest that, by infecting the fat body tissues, T. solenopsae may cause the down regulation of several proteins and peptides in the hemolymph of fire ant alates and dealates.