Various acetylated chitosan derivatives and mixtures of chitin and chitosan, covering the range of the degree of deacetylation (DDA) from 0-100% were analyzed by 1 H-NMR spectroscopy and infrared spectroscopy. The use of the 1070 cm - 1 or 1030 cm - 1 absorption band as an internal standard in the determination of DDA from the absorbance of the amide I bands at 1655 cm - 1 and 1630 cm - 1 or the amide II band at 1560 cm - 1 was studied. There is a good correlation between the results from IR spectroscopy and those from 1 H-NMR spectroscopy.