Results of ultrasound-assisted transesterification process for biodiesel production from soybeans is shown in Table 4. The physical properties of biodiesel produced with ultrasound-assisted transesterification and mechanical stirring were within the ASTM standard range. High flash point of biodiesel produced by using ultrasonication (170 °C) was higher than the biodiesel produced using mechanical stirring (150 °C). Sulfur content of both soybean oil biodiesel samples was lower than the maximum standard value. Water content of both samples were higher than standard range.