An oligoarray analysis was conducted to determine the differential expression of genes due to phenobarbital exposure in Drosophila melanogaster (w(1118) strain) third instar larvae. Seventeen genes were observed to be induced with increased expression by a statistical analysis of microarrays approach with a q < or = 0.05. At q < or = 0.12, four more genes (Cyp12d1, DmGstd4, and two genes with unknown function) were found to be up-regulated, and 11 genes with unknown function were found to be down-regulated. Fifteen of these genes, Cyp4d14, Cyp6a2, Cyp6a8, Cyp12d1, Cyp6d5, Cyp6w1, CG2065, DmGstd6, DmGstd7, Amy-p/Amy-d, Ugt86Dd, GC5724, Jheh1, Jheh2 and CG11893, were verified using quantitative real time polymerase chain reaction. Some of these genes have been shown to be over-transcribed in metabolically DDT-resistant Drosophila strains.