A convenient and efficient procedure for the Friedel–Crafts acylation of aromatic compounds with carboxylic acids in the presence of P2O5/SiO2 is described. Both aromatic and aliphatic carboxylic acids reacted easily to afford the corresponding aromatic ketones. The use of non- toxic and inexpensive materials, simple and clean work-up, short reaction times and good yields of the products are the advantages of this method.