This work investigates the biodiesel production with supercritical methyl acetate in a tubular packed bed reactor. The influence of temperature, oil to methyl acetate mass ratio and reaction time was evaluated throughout experiments performed at pressure of 20 MPa. The temperature ranged between 300 and 400 degrees C, and the oil to methyl acetate mass ratio varied between 1:2 and 1:5. Two different oils with very different composition and free fatty acid content were utilized: soybean oil and macauba oil. According to the results obtained, 44% was the highest ester yield obtained for soybean oil at 350 degrees C, 45 min of reaction time and oil to methyl acetate mass ratio of 1:5. In this condition a decomposition of 48% was also achieved. For the macauba oil, the highest ester yield was 83% with a decomposition of 17%, achieved at 325 degrees C, oil to methyl acetate mass ratio of 1:5 and 45 min of reaction time. A comparison between the oils allows pointing out that macauba oil presented better performance, probably due to its high free fatty acid content. (C) 2012 Elsevier B.V. All rights reserved.