Background: A major impediment to successful chemotherapy is intrinsic or acquired multidrug resistance (MDR).Breast cancer resistance protein (BCRP), an ATP-binding cassette (ABC) transporter, confers resistance to various anticancer drugs like adriamycin.Silencing of BCRP with small interfering RNA (siRNA) could be a promising approach to overcome MDR of cancer, although delivery of siRNA remains a major hurdle to fully exploit the potential of siRNA-based therapeutics.