This communication describes a novel approach for developing ultrathin-film chemical microsensor materials by anchoring a covalently bound, self-assembled C60 multilayer on the surface acoustic wave (SAW) resonator via a siloxane bond linkage. The multilayer structure has been characterized by optical absorption, surface acoustic wave mass transduction, and polarized variable-angle internal attenuated total-reflection infrared spectroscopy (PVAI-ATR-IR). On a 200-MHz SAW device, typical mass loading from saturated organic vapors at room temperature causes a rapid reversible frequency shift of approximately 10 kHz. The C60-based microsensors are most selective to those organic vapors such as decahydronaphthalene, perchloroethylene, and toluene, which is consistent with the fact that these are good organic solvents for buckyballs.