Polysaccharides are one of the central classes within high-molecular compounds of natural origin, which serve crucial biological functions within living organisms. The polysaccharides representative studied within the framework of this paper is linear pullulan. Such a unique polymer as pullulan finds useful applications in pharmaceutics, cosmetics, food industry, etc. [1, 2]. A particular feature of pullulan in biophysical studies is the calibration purposes for size exclusion chromatography (SEC). The molecular characteristics of pullulan and the dimensions of its molecules have been discussed in a number of papers [2, 3]. In present work the persistence length of pullulan chains was accurately defined by studying homologous series of 8 samples commercially distributed pullulan (SEC standard) produced by ‘Polymer Laboratories’ within wide range of molar masses: 5.9