The effect of structure and doping on the properties of the iron-CNT interface is studied using ab initio electronic structure methods. We consider two interface structures, one with a metal bump onto which the CNT is docked and one without. The CNT band gap and the position of the Fermi energy are insensitive to the interface structure, however transmission is affected by structural change, with larger transmission occurring for the interface with the dock. Additionally, we study a boron doped CNT in contact with iron and find that the CNT becomes metallic and an Ohmic contact is formed. (C) 2014 Elsevier B.V. All rights reserved.