The defatted rice bran (DRB), a by-product of rice industrialization, is a high-carbohydrate feedstock, which enables the production of bioethanol. The low ultrasound frequency (20-100 kHz) promotes great agitation in aqueous solutions, because of the phenomenon of cavitation, allowing greater speed of chemical reactions and stimulating cell growth. This exploratory study aimed to evaluate the process of ultrasonic assisted fermentation of DRB hydrolyzed. First, the enzymatic hydrolysis of DRB in reactor (TE-2003 / 3,0-E2, Tecnal) was performed using commercial enzymatic preparations containing protease, α-amylase and amyloglucosidase. The hydrolyzed (containing 47 ± 3 g/L of fermentable sugars) was submitted to fermentation by Saccharomyces cerevisiae in the ratio of 10% (v/v). The incubation was made in orbital shaker (SL 221, Scientific Solab) at 30 °C and 100 rpm, for 10 hours. Three different tests were performed in triplicate, one control (EC) (without ultrasound application), and the other two with ultrasound application, at 37 kHz (E37) and 80 kHz (E80). Ultrasound was applied from the sixth hour of fermentation, at regular intervals of 2 hours in ultrasonic bath (Ultra-Bohn, Elma, E 30H), with an exposure time of 105 seconds and 70% of power. The fermentation was monitored by taking samples every 2 hours. The results were treated using software STATISTICA 7.0 (Statsoft Inc., Tulsa, U.S.A.). The cellular productivity (0.67 ± 0.01 gcells/(L · h)) was higher in the E80 assay compared to the others, indicating a stimulation of the cell growth promoted by the ultrasound, without significantly altering the ethanol production (p<0.05). As there was no negative effect on the other evaluated results, subsequent studies will be performed using statistical optimization techniques to define ultrasound parameters that positively influence on fermentative kinetics.