To assess a possibility of the measurement of the relative concentration of main gasoline components under varied conditions, we studied the absorption of electromagnetic radiation by these components in the mid-IR region. The results for the absorbance of gasoline with varying concentrations of components, obtained using Fourier-transform IR spectroscopy are presented. The use of multidimensional difference spectra of gasoline is the most effective and informative way to perform measurements. The high sensitivity of the difference spectra to changes in the composition and concentrations of the main gasoline components is demonstrated.