Background StAR-related lipid transfer domain containing 7 (StarD7) is a member of the START-domain protein family whose function still remains unclear. Our data from an explorative microarray assay performed with mRNAs from StarD7 siRNA-transfected JEG-3 cells indicated that ABCG2 (ATP-binding cassette sub-family G member 2) was one of the most abundantly downregulated mRNAs. Methodology/Principal Findings Here, we have confirmed that knocking down StarD7 mRNA lead to a decrease in the xenobiotic/lipid transporter ABCG2 at both the mRNA and protein levels (−26.4% and −41%, p