Platinum and platinum/nickel alloy electrocatalysts supported on graphitized (gCNT) or nitrogen doped carbon nanotubes (nCNT) are prepared and characterized. Pt deposition onto carbon nanotubes results in Pt "needle" formations that are 3.5 nm in diameter and similar to 100 nm in length. Subsequent Ni deposition and heat treatment results in PtNi "needles" with an increased diameter. All Pt and Pt/Ni materials were tested as electrocatalysts for the oxygen reduction reaction (ORR). The Pt and Pt/Ni catalysts showed excellent performance for the ORR, with the heat treated PtNi/gCNT (1.06 mA/cm(2)) and PtNi/nCNT (0.664 mA/cm(2)) showing the highest activity. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.022202esl] All rights reserved.