Liberation of bitumen from sand grains is a key step on processing oil sands using water-based extraction processes. In this study, effects of diluent addition on bitumen liberation from a solid surface were investigated under various conditions, including the washing temperature, pH value of the water, and washing time. It was found that more effective bitumen liberation could be achieved by adding diluents, such as kerosene and fatty acid methyl ester (FAME), in the bitumen. Especially; FAME addition was found more efficient to accelerate bitumen liberation than that of kerosene. Rheological characterization showed that bitumen viscosity was greatly decreased with diluent addition, which was responsible for the improved bitumen liberation. The findings in this study might find their applications in the oil sands processing industry.