Smart polymers and nanofibers are potentially intriguing materials for controlled release of bioactive agents. This work describes a new class of pH responsive nanofibers for drug delivery systems with controlled release properties. Initially, poly(4-vinylbenzoic acid-co-(ar-vinylbenzyl) trimethylammonium chloride) [poly(VBA-co-VBTAC)] was synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. Then, ciprofloxacin was chosen as the model drug for the release study and encapsulated into pH-responsive polymeric carriers of poly(VBA-co-VBTAC) nanofibers via electrospinning. The morphology of the electrospun nanofibers was examined by scanning electron microscopy (SEM). The structural characteristics of the pH responsive nanofibers were investigated by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The release measurements of ciprofloxacin from pH responsive nanofibers were also performed by high-performance liquid chromatography (HPLC) analysis. To show the pH sensitivity of these nanofibers, the release profile of ciprofloxacin was examined under acidic, neutral and basic conditions. The results indicate that pH responsive nanofibers can serve as effective drug carriers since the release of ciprofloxacin could be controlled by changing the pH of the environment, and therefore these drug loaded pH-responsive nanofibers might have potential applications in the biomedical field. This journal is © The Royal Society of Chemistry.