ZnFe2O4 was synthesised by precipitation method. The photocatalytic activity of ZnFe2O4 was investigated by carrying out the photocatalytic degradation of rose Bengal dye under visible light. The degradation rate of the dye was observed by measuring its absorbance at regular time intervals at 540 nm. Effect of various parameters like pH, concentration of dye, amount of semiconductor and intensity of light on rate of degradation was observed. The optimum rate was observed at pH = 7.0; rose Bengal = 5.0 x 10-6 M; zinc ferrite = 0.1 g and light intensity = 60.0 mWcm-2. The rate constant for a typical run was observed as 2.45 x 10-4 sec-1. A tentative mechanism has been proposed for the photocatalytic degradation of rose Bengal in presence of zinc ferrite involving hydroxyl radical as an active oxidizing species.