Bogor taro (Colocasia esculenta L. Schott) was a potential sources with high carbohydrate content due to its high amylose content however, the native starch of Bogor taro still have low quality in terms of physicochemical characteristics. The starch modification by acetylation method was known to be the outcome to enhance the functionality of the native starch. The purpose of this research was to produce RS4 (resistant starch type 4) through acetylation to enhance the functionality and physicochemical characteristics of the starch. This research was divided into three stages, which were preliminary step, stage I and stage II. Preliminary research was conducted to isolate the starch from Bogor taro. Stage I was the acetylation process by varying the concentration of acetic anhydride (5%, 10% and 20%). The best concentration, based on the acetyl percentage and degree substitution result, was used as the concentration in the stage II. The stage II was the acetylation process by varying the temperature and the time of reaction. The starch obtained from the best treatment was subjected to viscosity, color analysis, resistant starch, starch percentage, amylose and amylopectin content, solubility and swelling power, FTIR and proximate analysis. The higher concentration of acetic anhydride resulted in higher value of acetyl percentage and degree substitution. Moreover, 45oC and 15 minutes were the optimum reaction condition to obtain allowable acetylated Bogor taro starch (degree substitution ≤ 0.2). Acetylation process affected the characteristic of the starch by increasing the acetyl percentage, degree of substitution, resistant starch percentage, amylose content, and L value, but decrease the viscosity, amylopectin content, solubility and swelling power, as well as changed the chemical structure of the Bogor taro starch.