The infrared analysis of ultrathin films on a thin glass slide often has a problem that optical interference fringes appear strongly on the absorption spectra due to multiple reflections in the glass. In the present study, the infrared multiple-angle incidence resolution spectrometry (MAIRS) has been employed to remove the fringes from the spectra of single- and five-monolayer Langmuir-Blodgett (LB) films of cadmium stearate deposited on a thin glass plate. As a result, it is preliminarily suggested that an ultrathin film on a thin glass substrate can be successfully analyzed by FT-IR spectroscopy. (C) 2006 Elsevier B.V. All rights reserved.