The kinetic stability of oil droplets in water phase was studied in the presence and absence of chemical demulsifiers. In the demulsification process, the flocculation and coalescence processes were investigated, by fitting the experimental data to a model kinetic equation, as a function of temperature, agitation speed, demulsifier concentration and type, etc. Without any demulsifier, the demulsification process followed a simple flocculation mechanism. In the presence of demulsifier, however, the destabilization kinetics was complicated, including both flocculation and coalescence processes. The rate of demulsification was controlled by coalescence process in the beginning and by the flocculation process at later under a batch experimental condition. As temperature or demulsification concentration increased, the coalescence behavior increased with the flocculation rate constant followed Arrehenius-type. It was observed that an optimal demulsifier concentration and agitation speed existed to procure a maximum demulsification accomplishment.