Dynamic interfacial tension between bitumen-in-toluene solutions (0.1-10 wt %) and aqueous sodium hydroxide solutions (0-5 wt %) were measured by drop volume method. The results of these measurements were analyzed on the basis of two models. The two models, based on diffusion-controlled adsorption, provided good fits to the dynamic interfacial tension data. The kinetic parameters and equilibrium interfacial tension were derived and were found to depend on both bitumen concentration in the oil phase and sodium hydroxide concentration in the aqueous phase. Equilibrium interfacial tensions decrease considerably with the increase of the concentration of bitumen or sodium hydroxide.