ATP-binding cassette (ABC) transporters are involved in the transport of substrates across biological membranes and are essential for many cellular processes. Of the fifty-six Drosophila ABC transporter genes only white, brown, scarlet, E23 and Atet have been studied in detail. Phylogenetic analyses identify the Drosophila gene dMRP/CG6214 as an orthologue to the human multidrug-resistance associated proteins MRP1, MRP2, MRP3 and MRP6. To study evolutionarily conserved roles of MRPs we have initiated a characterization of dMRP. In situ hybridization and Northern analysis indicate that dMRP is expressed throughout development and appears to be head enriched in adults. Functional studies indicate that DMRP is capable of transporting a known MRP1 substrate and establishes DMRP as a high capacity ATP-dependent, vanadate-sensitive organic anion transporter.