Anomalous coherent X-ray diffraction in Bragg geometry is a promising technique to study three-dimensional composition and strain fields in nanostructures. This paper presents results of coherent X-ray diffraction experiments on single Ag/Au core-shell nanowires with a typical diameter of 100 to 300 nm in the as-prepared state and during in-situ heating. Experimental coherent diffraction patterns are compared with finite-element simulations. Moreover, experimental constraints owing to radiation damage are discussed. (C) 2012 Elsevier B. V. All rights reserved.