Plasmid-mediated quinolone resistance determinants, including Qnr peptides and AAC(6-)-Ib-cr, are increasingly identified worldwide among various clinical isolates of Enterobacteriaceae. Very recently, a novel plasmid-mediated fluoroquinolone-resistant determinant, QepA (quinolone efflux pump), was first identified in an Escherichia coli clinical isolate from Japan and later found also in an E. coli isolate in Belgium, and both qepA-harboring E. coli isolates contained the rmtB gene encoding a 16S rRNA methyltransferase. Our previous study showed that rmtB was highly prevalent among E. coli isolates from pigs in China. The aim of this study was to investigate the prevalence of plasmid-mediated quinolone resistance determinants among rmtB-producing E. coli isolates from pigs in China and to identify the association of the qepA gene with rmtB. One hundred fifty-one E. coli isolates were obtained from pig feces sampled at two pig farms from 2005 to 2006, and 48 of them were identified as producers of RmtB. Screening for qepA, qnrA, qnrB, qnrS, and aac(6-)-Ib-cr genes was carried out by PCR amplification among the 48 rmtB-positive isolates, with positive results confirmed by direct sequencing. Overall, qepA, qnrB, qnrS, and aac(6-)-Ib-cr were detected in 28 (58.3%), 1 (2.1%), 9 (18.8%), and 6 (12.5%) of 48 RmtB-producing E. coli isolates, respectively. The qnrB gene was identified as qnrB6 allele, and the qnrS genes were confirmed as qnrS1 (four isolates) and qnrS2 (five isolates) alleles by sequencing. Four isolates with uniform pulsed-field gel electrophoresis (PFGE) patterns harbored qepA, qnrS2, and aac(6-)-Ib-cr genes concurrently. To investigate the association of rmtB and qepA, rmtB-positive E. coli transconjugants were subjected to PCR amplification of qepA.