The adenosine triphosphate binding cassette (ABC)-transporter ABCC2 (MRP2/cMOAT) can mediate resistance against the commonly used anticancer drugs cisplatin and paclitaxel. To overcome the ABCC2-depending drug resistance, two specific anti-ABCC2 small interfering RNAs (siRNAs) were designed for transient triggering of the gene-silencing RNA interference (RNAi) pathway in the cisplatin-resistant human ovarian carcinoma cell line A2780RCIS. Since both siRNAs showed biological activity, for stable inhibition of ABCC2 a corresponding short hairpin RNA (shRNA)-encoding expression vector was designed. By treatment of A2780RCIS cells with this construct, the expressions of the targeted ABCC2 encoding mRNA and transport protein were inhibited. These effects were accompanied by reversal of resistance against cisplatin and paclitaxel. Thus, the data demonstrate the utility of the analyzed RNAs as powerful laboratory tools and indicate that siRNA- and shRNA-mediated RNAi-based gene therapeutic approaches may be applicable in preventing and reversing ABCC2-depending drug resistance.