The mixing time required to achieve 99.5% of homogeneous concentration in a vibratory disk tank has been measured by a pulse injection method of NaCI solution. The mixing time, tm has been well correlated by where D is the tank inside diameter, Pw, the power requirement per unit volume, V the tank volume, A the amplitude of disk vibration, f the frequency, p the liquid density and d the disk diameter. It is also found that liquid mixing in the vibratory disk tank is mainly controlled by turbulent mixing phenomena rather than by convective flow.