Cassava production has increased consistenly in Indonesia. Cassava contains toxic substances, including of cyanide acid. Another, it has low content in protein, minerals, and vitamins. Therefore, a special proccessing is important prior to consumption. In this study, modified cassava production without any additional nutrients at different microorganisms and fermentation times, was investigated. Proximate and minerals composition of fermenting flour were also presented. It was found that at the microbial to cassava mass ratio of 1% for fermentation time of 120 h, L. plantarum, S. cereviseae, and R. oryzae on cassava can increase the levels of protein from 1.92% to 8.58%, 2.29%, and 4.72%, respectively. In addition, it can reduce starch content after fermentation in a number of 55.40%, 71.03%, and 48.20%, respectively. Moreover, the levels of cyanide acid was decreased from 17.5 mg/kg to 1.8, 3.28, and 3.17 mg/kg, respectively