Some natural and semisynthetic carotenoids were examined by means of FT-IR spectroscopy. The IR bands of the characteristic functional groups (CH3, CH2, CC, CO, OH, etc.) were assigned when possible. Some special functional groups - without H-atoms - such as CCC, 'cross epoxides', etc., which cannot be easily identified by 1H-NMR methods, were also detected in the FT-IR spectra.