Abstract—A systematic assignment of bands observed in the range of 1800–800 ^–1 cm when measuring samples in KBr pellets based on the example of the analysis of infrared spectra of DNA complexes with dichlorodiammineplatinum(II) was performed. Based on the performed decomposition of the spectra of DNA and its complexes with dichlorodiammineplatinum(II), it was shown that the results are in good agreement with the direct structural data, as well as with previous measurements in solution. It was also shown that markers of the A- and B-forms of DNA are simultaneously observed in the DNA spectra in KBr pellets.