Scandium trifluoromethanesulfonate (Sc(OTf)3) was found to be a novel catalyst for Friedel-Crafts acylation. The reactions of substituted benzenes with acid chlorides or anhydrides proceeded smoothly even in the presence of a catalytic amount of Sc(OTf)3. While Sc(OTf)3 is a reusable catalyst similar to lanthanide trifluoromethanesulfonates, its catalytic activity is much higher than that of lanthanide analogs.