The degradation of Rhodamine-B (RB) in aqueous solutions was investigated in this study under the influence of ultrasound irradiation (20 kHz) in the presence of titanium dioxide (TiO2) and niobium pentaoxide (Nb2O5) heterogeneous catalysts. The effects of different factors such as catalyst quantity (0.25, 0.5, 0.75, 1.0, 1.25 g/L), initial concentration of RB (10, 20, 30, 40, 50 ppm) and pH (3, 5, 7, 9, 11) were examined. The optimal catalyst dose was found to be 1.25 g/L of TiO2, Nb2O5and the maximum percentage of RB degradation was observed at pH 3 for the TiO2and Nb2O5catalysts. In the presence of TiO2and Nb2O5, the percentage degradation of RB under ultra-sonication in aqueous solutions is up to 85% and 81% respectively. © 2021 Elsevier Ltd. All rights reserved.