Asphaltene dispersants are used in the paraffinic solvent-based bitumen froth treatment process to increase the fluidity of underflow that is made of precipitated asphaltene aggregates, water, and mineral solids. In this work, the yield stress of the underflow was used to define the fluidity of underflow and to evaluate the performance of asphaltene dispersants. The performance of asphaltene dispersants was also examined using microscope, tensiometer, and Dean Stark composition analysis. Results show that asphaltene dispersants prevent asphaltene particles from forming large aggregates by modifying their surface properties. Application of an effective asphaltene dispersant not only results in much lower yield stress of the underflow, but also brings more mineral solids and asphaltenes from rag layer to the underflow.