The fluorescence and polarography methods are used to establish certain differences in conformation characteristics of transcriptionally active and repressed forms of rat liver chromatin. The data obtained prove the nucleo-soma ability to aggregation in the repressed chromatin and confirm a decondensed character of packing in transcriptionally active chromatin. It is supposed that these peculiarities are connected with different content of calcium and iron ions in the studied fractions of chromatin. Lipids, being the components of chromatin fractions, are packed with proteins in a form of bilayer structure. The packing character is similar in the both chromatin fractions. But microviscosity of the lipid bilayer in transcriptionally active chromatin is significantly lower than that in the repressed one and this may be one of reasons of different transcriptional activity and ability to peroxidation of the studied chromatin forms.