Biodegradable films are widely exploited among scientists nowadays. Their positive environmental impact, besides their potential to promote better food conservation and an increase in shelf life motivate research in this field. Availability, low cost and biodegradability of starch increase the interest of using this material to produce biodegradable films. However, starch films tend to be brittle and they need addition of a plasticizer to enable their usage. In this work, starch films were synthesized with different carboxylic acids as plasticizers, aiming to observe the effect of the acids' chain size in the final films properties. Oxalic, succinic and adipic acids were used. The materials were produced by casting and characterized by DSC, TG, XRD, FTIR and SEM. It was observed that the acids chain size influenced on the thermal and structural properties of the films.