Alkylation of benzene with isopropanol to produce cumene was investigated using a MCM-41 aluminosilicate as catalyst. The MCM-41/gamma-Al2O3 catalyst, activated by means of a Liquid extraction method, mainly contained strong Lewis acid sites. After the activity of the composite catalyst was stabilized, it was observed that, in the isopropylation of benzene, cumene was the major product. The high cumene selectivity could be due to the low acid site concentration in the MCM-41 material, and the rapid diffusion of cumene in the broad channels of this mesoporous framework.