For the development of a low-cost MgB2 superconductor the "powder-in-tube" (PIT) technique is investigated. Mechanically alloyed MgB2 powder provides a favorable microstructure and phase composition for the low temperature preparation of MgB2 tapes with superconducting properties. The composition of sintered bulk samples and Fe-clad MgB2 tapes made of mechanically alloyed MgB2 has been investigated by Auger micro-analysis. Due to the process the samples contain about 15% oxygen. Pure MgB2 crystallites were investigated as standard for stoichiometry and peak shape analysis. (c) 2005 Elsevier B.V. All rights reserved.