In this study, the experimental optimization of ultrasound assisted biodiesel production in presence of heterogeneous catalyst was investigated. Three catalysts namely; CaO, calcined dolomite and calcium diglyceroxide (CaDG) were taken into account for comparative purpose. D-optimal experimental plan was applied to obtain regression models which were subsequently used for the detection of optimum process conditions. Maximum biodiesel yields were calculated as 98.7%, 95.9% and 86.3% for CaO, calcined dolomite and CaDG respectively. Furthermore, supplemental experiments were conducted around optimum process conditions to test the validity of the regression models and to refine the optimum results. Finally, in the case of CaO catalyst, maximum biodiesel yield (99.4%) was obtained at the following conditions; catalyst loading: 5.35% (wt.of oil), methanol/oil ratio: 7.48, ultrasonic power: 40 W, time: 150 min, and reaction temperature: 60 degrees C. (C) 2017 Elsevier Ltd. All rights reserved.