This study involves the photo-catalytic degradation of rhodamine-B (RB) employing heterogeneous photo-catalytic process. Photo-catalytic activity of different semiconductors such as titanium dioxide (TiO2) and niobium pentaoxide (Nb2O5) has been investigated. An attempt has been made to study the effect of process parameters through amount of catalyst, initial concentration of dye, and operating pH on photo-catalytic degradation of RB. The experiments were carried out by varying pH (2-11), amount of catalyst (0.25-1.5 g/L), and initial concentration of dye (10-50 mg/L). The optimum catalyst dose was found to be 1 g/L of TiO2 and 1.25 g/L of Nb 2O5 for RB at 30 mg/L respectively. The maximum rate of degradation was observed in acidic medium at pH 3 for catalyst TiO2 and Nb2O5 respectively. It was observe that the photocatalytic activity of TiO2, is greater than Nb2O 5.