In-situ transesterification (simultaneous extraction and transesterification) of Chinese tallow tree seeds into methyl esters using a batch microwave system was investigated in this study. A high degree of oil extraction and efficient conversion of oil to biodiesel were found in the proposed range. The process was further optimized in terms of product yields and conversion rates using Doehlert optimization methodology. Based on the experimental results and statistical analysis, the optimal production yield conditions for this process were determined as: catalyst concentration of 1.74 wt.%, solvent ratio about 3 (v/w), reaction time of 20 min and temperature of 58.1 degrees C. H+NMR was used to calculate reaction conversion. All methyl esters produced using this method met ASTM biodiesel quality specifications. (C) 2015 Elsevier Ltd. All rights reserved.