BACKGROUND Starch degradation is an important process that can increase starch utilization in some industrial applications. In many polysaccharide compounds, the addition of salt is an alternative method to enhance the structural degradation of starch by sonication. This study aimed to investigate the effect of sonication in aqueous NaCl solution on the structural degradation of cassava starch. RESULTS This method produces reducing sugar which its amount is relatively smaller than the amount of total dissolved solid product. The maximum total reducing sugar (TRS) was 0.365 ± 0.005 kg m-3 (or about 7.3 mg g-1 ) that resulted by S50 for 60 min reaction. The increase of sonication amplitude was in line with the increase of granule defect in SEM image. X-ray diffraction (XRD) showed that the degradation process was characterized by rupturing of the amorphous region. CONCLUSIONS The structural alteration and the increase in NaCl weight suggest that this process may become a useful method for starch modification. © 2020 Society of Chemical Industry.