In the present work, a new method for the analysis of the amino group content in different amino polydimethylsiloxanes (silicones) by infrared analysis has been developed. Because of the low ratio of the amino functional group present in the silicone molecules (which is sufficient to modify their properties), its analysis by traditional techniques is tedious and complex. The novelty of this study relies on the fast and easy application of the Fourier transform infrared spectroscopy (FTIR) to the quantitative analysis of these groups by the use of low intensity bands. With this purpose, spectra obtained from samples with different polymerization degree and/or amino group content have been compared to select a characteristic band for the amino group and another for the siloxane bond to be used as reference band. From the calibration curve obtained, two different samples of known amount of amino group content were analyzed obtaining a good correlation with the value found by the experimental design.