Ultrasound-assisted biodiesel production from waste cooking oil catalyzed by hydrotalcite (HT) catalyst prepared using combustion method was studied. Two important parameters in the HT synthesis i.e., calcination temperature (550-850 degrees C) and fuel type (saccharose, glucose and fructose) were particularly investigated. The dependence of HT's characteristics on the synthesis parameters and correlations with their catalytic performance under ultrasound condition were successfully elucidated. The HT catalyst prepared using saccharose and calcined at 650 degrees C was the best catalyst to be used in the transesterification reaction. It showed high biodiesel yield (about 76.45%) in just 60 min in the presence of low ultrasound amplitude (similar to 11 kHz). The enhancement effect of ultrasound was successfully demonstrated. The reaction only needed short reaction time (about 1 h) to give a biodiesel yield of up to 76.45% compared to conventional stirring method that needed about 5 h to achieve the same yield. (C) 2016 Elsevier B.V. All rights reserved.