Starch is polysaccharide made from minute granules. It is used as food additive to improve texture of numerous foodstuff and a basic source of energy in human nutrition (more than 50%). In food industry modified starch is mostly used to achieve specific functional properties, for example, thickening, water retenrtion, to provide proper texture, etc. The aim of this research was to prepare double modified wheat (two varieties: Golubica and Srpanjka) and potato starches by chemical process of modification; acetylation with acetic anhydride (AA, 8%) followed by cross-linking with sodium tripolyphosphate (STPP, 2,5 either 5%). Rheological paste properties (natural and modified starch) were tested by Brabender Micro visco analyzer, and swelling power and solubility index after starch modification were determined. Results showed that starch type and amount of reagent for cross-linking (2,5 or 5% STPP) caused lowering or increasing viscosity of starch paste and lowering or increasing gelatinization temperature compared natural starch. Paste viscosity and gelatinization temperature of modified starches depended on degree of cross-linking and degree of substitution which depended on starch type and reagent amount. Starch modification with acetic anhydride resulted in substitution reaction, while STPP resulted in crosslinking and substitution reaction by which monostarch phosphate(starch ester) was formed in addition to distarch phosphate.