The effect of ultrasound on the photocatalytic oxidation kinetics of elemental sulphur particles catalyzed by titanium dioxide was studied using a conductivity method to follow the reaction. The simultaneous use of photocatalyst and ultrasound have a positive effect on the reaction. The zero-order oxidation rate constant of sulphur, reached after an activation period of approximately 150 min, was about 20 times higher when the reactor was sonicated, using an ultrasonic processor of 30 kHz, compared to the rate found in its absence. Finally, when the amount of sulphur is changed in the reactor, saturation kinetics seems to be the most appropriate model to describe the oxidation process in the presence of ultrasound and, in the other hand, when titanium dioxide was increased, a maximum rate was achieved when 0.56 g/L TiO2 were used.