A noninvasive stability-indicating assay method utilizing Fourier Transform-Infrared/Attenuated Total Reflectance (FT-IR/ATR) Spectrometry for the determination of propylene carbonate in pharmaceutical formulations is described. The linearity of propylene carbonate response was studied by use of its carbonyl stretching frequency after spectral subtractions were performed to remove interfering bands. Analyses were performed on aqueous solutions of propylene carbonate, an aqueous cream formulation, and an anhydrous ointment spiked with propylene carbonate.