Two methods to characterize morphologically the internal structure of the walls of polymeric microcapsules were developed. Microcapsules should be opened in order to visualize either by scanning electron microscopy or transmission electron microscopy their cross-section wall morphology but without damaging the porous structure. Therefore, adequate cutting conditions are required. Novel micrographs of internal walls of rnicrocapsules were obtained. (c) 2007 Elsevier B.V. All rights reserved.