Potato starch was segregated on large and small granules fractions. Native starch and obtained fractions were subjected to reaction of phosphorylation by sodium trimetaphosphate. On each kind of preparation selected physicochemical properties were analysed. Based on obtained results it was stated that potato starch and its fractions phosphorylation caused the greatest phosphorus incorporation into small granules fraction in comparison with big granules fraction and native starch. Obtained starch phosphates were characterised by lower amylose content and larger viscosity values in comparison with control samples. Starch phosphate obtained from small granules fraction of the potato starch were characterised by lower amylose content and higher viscosity of paste, compared to phosphates obtained from native starch and large granules fraction.