Final full-text version of the paper available at Angewandte Chemie International Edition website: http://dx.doi.org/10.1002/anie.200390304.-- Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2003/z50514_s.pdf or from the author.-- Corrigendum published online 17 Jun 2003, DOI: http://dx.doi.org/10.1002/anie.200390498.Corrigendum text: "In the Communication “A Zeolite Structure (ITQ-13) with Three Sets of Medium-Pore Crossing Channels Formed by 9- and 10-Rings” by A. Corma et al. in Angew. Chem. 2003, 115, 1188–1191; Angew. Chem. Int. Ed. 2003, 42, 1156–1159, it should have been made clear early on in the manuscript that the synthesis of the ITQ-13 material was first reported in a patent published in 2002 (T. Boix, M. Puche, M. A. Camblor, A. Corma, US Patent 6 471941B1, 2002; reference [12] in the manuscript). Furthermore, owing to an editorial error the reference to this patent was wrongly introduced into the Experimental Section, where reference [13] should read reference [12] and viceversa. We apologize to our readers and to the authors of the above mentioned patent if this mistake has resulted in any misunderstanding".ZSM-5 (MFI code) is a medium-pore zeolite that has 10-ring channels with pore diameters of 5.1×5.5 and 5.3×5.6 Å, and has been a very successful zeolite for shape-selective catalysis that has found many industrial applications.By considering the structure of ZSM-5 and the catalytic results obtained in the fields of oil refining and petrochemistry, one could intuitively predict that a medium-pore zeolite with intersecting channels and pore dimensions that are slightly smaller than those of ZSM-5 should enhance the possibilities for shape-selective catalysis in the fields of fluid catalytic cracking (FCC) additives, catalytic dewaxing, toluene disproportionation, alkylation of aromatics, isomerization of alkylaromatics, and so forth.Herein, we will describe such a zeolite structure (ITQ-13), which exhibits three sets of intercrossed medium-pore channels; a 9-ring channel, with a pore aperture of 4.0×4.9 Å, runs parallel to the crystallographic a axis, a 10-ring channel system (4.8×5.7 Å) runs parallel to the c axis, and another 10-ring set of channels (4.7×5.1 Å) runs parallel to the b axis.We thank Spanish CICYT (projects MAT 2000-1392 and MAT 2000-1167-C02-01) for financial support. A.C., M.P., and F.R acknowledge EXXON-Mobil for valuable support. G.S. and S.J.T thank the EPSRC for financial support.Peer reviewed