Na 2 (Mo 2 V O 4 EDTA).4H 2 O crystals have been prepared in pure form. Kinetics for the oxidation of the compound by S 2 O 8 2Ϫ have been studied spectrophotometrically in dilute sulphuric acid medium. The effects of hydrogen ion concentration, metal ion concentration, S 2 O 8 2Ϫ ion concentration, and temperature on the process have been studied. Rate equations have been derived to explain the experimental observations. On the basis of the observations, suitable mechanisms have been suggested. The kinetic parameters E*, ⌬H ϶ , and ⌬S ϶ of the process have also been determined.