We describe here the cloning and characterization of a cDNA encoding the glutathione S-transferase (GST) from the bumblebee Bombus ignitus. The Delta-class B. ignitus GST (BiGSTD) gene spans 1668 bp and consists of four introns and five exons that encode 216 amino acid residues with a calculated molecular weight of approximately 24561 Da and a pI of 8.03. The N-terminal domain of BiGSTD has a conserved Ser residue, as well as conserved Lys, Pro, Glu, Ser and Tyr residues that are involved in the GSH-binding site of GST. The BiGSTD showed 60% protein sequence identity to the Bombyx mori GSTT1, 58% to Musca domestica GST, 57% to Drosophila melanogaster GST, and 55% to Anopheles gambiae GST1. BiGSTD was close to the insect-specific Delta class of GSTs in a phylogenetic tree. Northern blot analysis showed that BiGSTD is highly expressed in the fat body and midgut, and less so in the muscles of B. ignitus worker bees.