We have constructed cDNA library from the larvae whole body of the firefly, Pyrocoelia rufa. Single direct partial sequencing of anonymous cDNA clones was performed to obtain genetic information on the firefly, P. rufa, of which genetic information is currently not available. This expressed sequence tags (EST) analysis of the 54 clones (54%) showed significant homology to the known genes registered in GenBank. Of these clones, twenty-four were related to the known insect genes, but these clones were not matched to previously identified firefly genes. Putative functional categories of these clones showed that the next abundant genes were associated with energy metabolism.