We present the different elaboration steps of a composite formed of carbon nanotubes (CNT) carpet embedded in an epoxy polymer. Detailed characterization at each step of the elaboration process is performed. The good alignment of CNT in as-grown carpets is kept all along the elaboration process of the composite, as it is measured at both macro and microscopic scales by X-ray scattering. We also ensured by X-ray fluorescence measurements that the iron-based catalyst particles used for the synthesis were removed from the carpet after a high temperature post-annealing treatment. These measurements give valuable information for further applications involving unidirectional nanotube composites and membranes, where CNT alignment is a key parameter. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39730.