9 pages, 8 figures.-- Printed version published on Jul 18, 2007. In this work, the textural properties of a series of whole anthracitic-derived fly ashes sampled in eight hoppers from the electrostatic precipitators and their sized fractions (from >150 to <25 μm) are investigated. Data from N2 adsorption isotherms at 77 K, helium density, and mercury porosimetry have contributed to establish a relationship between the Brunauer−Emmett−Teller (BET) surface areas, VTOT, porosity, carbon content (the type of fly ash carbons), and Hg retention in these fly ashes. The unburned carbons in these ashes are macroporous materials, and they are different from the carbons in fly ashes from classes C and F (the latter derived from the combustion of bituminous coals) and show different textural properties. These ashes represent the end member of the fly ash classes C and F with respect to certain textural properties. Although the BET surface area and VTOT values for the studied samples are the lowest reported, they increase with the increase in carbon content, anisotropic carbon content, and particle size of the ashes. Thus, a positive relationship between all these parameters and Hg capture by the coarser ash fractions was found. The finest fraction of carbons (<25 μm) represented an exception. Although it makes a significant contribution to the total carbon of the whole fly ashes and shows relatively higher surface areas and VTOT values, its Hg concentration was found to be the lowest. This suggests that the type of unburned carbons in the finest fraction and/or other adsorption mechanisms may play a role in Hg concentration. Because the textural properties of anisotropic carbons depend on their subtype and on their origin, the need for its differentiation has been evidenced. The financial support for this work was provided by the Spanish Ministerio de Educación y Ciencia (MEC) Grant of the Programa de Movilidad to I.S.-R. (ref PR2005-0168). The authors thank the Spanish power plant for providing the samples and CAER at the University of Kentucky (Lexington, KY) for providing facilities for developing this research work. Dr. B. Ruiz Bobes and E. I. González Suárez (INCAR-CSIC, Spain) are also thanked for their analytic work. Peer reviewed