The maximum yield of biodiesel obtained with the triple frequency approach, at 3:1molar ratio of methanol to oil with 1 wt.% potassium hydroxide as catalyst was 93% with a significantly reduced reaction time of 15 min as compared to 3 h required in case of conventional stirring to achieve 75% yield. The results of this investigation support that using multiple frequency ultrasonic irradiation is beneficial in intensifying the transesterification reaction.