In this study, tapioca starch was successfully modified through a crosslinking reaction with citric acid. Tapioca and citric acid were reacted by setting the conditions during the reaction such as the concentration of citric acid, time reaction, pH, and temperature. Citric acid was chosen as the crosslinker as it is Generally Recognized as Safe (GRAS) for food and its carboxylic groups can easily form crosslinking reactions with hydroxyl groups of starch through formation of ester at both ends of citrate. Characterization of the product with FT-IR showed that a peak at 1720 cm-1 indicates the presence of ester groups in the product. Characterization with XRD showed that modified starch has a lower level of crystallinity. Based on the results of several characterizations of starch citrate products, the functional properties of starch also change, such as the decrease of swelling power, solubility, and viscosity. Digestibility of starch citrate also decreased by 25 % compared to normal starch.