The beneficial use of tung oil in pre-blended oil for the production of biodiesel was studied at various blending compositions of tung, canola and palm oils (C-BT, C-BC and C-BP). The effects of CBT, ultrasonic power (P-WUS) and sample loading (V-L) on the yield (Y-F) and the properties of acid value, iodine values (IV), kinematic viscosity (KV), density and cold filter plugging point (CFPP) were investigated. The pre-blending of tung oil with palm oil greatly decreases the CFPP of palm oil biodiesel, whereas the presence of canola and palm oils with tung oil reduces the IV and KV of tung oil biodiesel. For P-WUS/V-L = 0.92 -2.08 W/mL, C-BT can be as high as 60 wt.% with 30 wt.% C-BC and 10 wt.% C-BP to produce biodiesel with high Y-F and satisfactory qualities of the said properties. (C) 2012 Elsevier Ltd. All rights reserved.