In this work, a catalyst based on alumina impregnated with potassium iodide was synthesized and tested in the process of transesterification of rice bran oil with methanol. The reaction took place in a reflux system, with a molar ratio of 15:1 methanol:oil. The catalyst was prepared by impregnation of alumina with a solution of KI followed by calcination at 773 K for 3 h. The effect of concentration of the catalyst in the yield was verified in the range of 1-5 wt.%, and the properties of specific gravity and kinematic viscosity of the biodiesel were determined. The increasing of the yield of the reaction was observed for high amount of catalyst. When 5 wt.% of the catalyst was used in the process, the best results was obtained, with 95.2% yield. As expected, the specific gravity and kinematic viscosity decreased with the catalyst amount From TG analysis, it was observed a mass loss of 96.2%, evidencing the high activity of the catalyst for the process. (C) 2012 Elsevier B.V. All rights reserved.