We report on the fabrication of an amphiphilic random copolymer-based colorimetric and fluorescent chemosensor for Fe3+ ions that was prepared by free radical polymerization of a novel rhodamine-based Fe3+-recognizing monomer, R6GEM, with N-vinylpyrrolidone (NVP). Because of its amphiphilic property, the copolymer P(NVP-co-R6GEM) can self-assemble into micelles, which allows it to be used as a chemosensor in aqueous solution. Upon addition of Fe3+ ions to the micelle solution, visual color change and fluorescence enhancement were observed. Moreover, other metal ions did not induce obvious changes to the absorption and fluorescence spectra. The water dispersibility and biocompatibility of these polymer micelles could provide a new strategy for detecting analytes in environmental and biological systems. (C) 2011 Elsevier Ltd. All rights reserved.