Vapour phase oxidation of tetralin to 1-tetralone using molecular oxygen is reported for the first time on Cr and Fe substituted MCM-41 molecular sieves. Mesoporous monometallic Cr-MCM-41(Si/Cr 25, 50, 75 and 100), Fe-MCM-41(Si/Fe=25) and bimetallic Cr-Fe-MCM41(Si/(Cr + Fe) = 100) molecular sieves were synthesized by direct hydrothermal (DHT) process and characterized by XRD, ICP-AES, DR-UV-vis spectroscopy, EPR spectroscopy and SEM techniques. The conversion of tetralin and the selectivity for I -tetralone were studied in the temperature range of 473-623 K. The efficiency of all the catalysts was evaluated and compared for the oxidation reaction under atmospheric pressure. Among various catalysts under study, Cr-MCM-4 1 catalyst with Si/Cr = 25 exhibited maximum efficiency. The correlation between 1-tetralone selectivity and the catalysts physico-chemical characteristics is made. A reaction scheme is proposed for the oxidation of tetralin to 1-tetralone. The reaction is considered to occur in two steps: oxidation of tetralin to tetralol and oxidation of the latter to 1-tetralone, with the former process occurring over Cr3+ and the latter over Cr6+. (c) 2007 Elsevier B.V. All rights reserved.