The objective of this report is to give a characterization of MCM-41, in particular with respect to acidity and molecular sieve properties, with a view to using this mesoporous material in catalysis. The results obtained by TPAD measurements indicate that aluminosilicate MCM-41 behaves like a solid-state acid. Because of its high thermal stability this material is applicable as an active component in acid-catalysed cracking reactions at temperatures above 500 degrees C.