The non-edible oils of mahua and jatropha were transesterified using methanol and 1 wt % KOH as the catalyst. The effect of co-solvent and the kinetic study of the transesterification of mahua oil is being reported here for the first time. Kinetics, modeled as a single-step reaction, revealed that the order of the reaction is 2 with respect to the triglyceride concentration and 1 with respect to the methanol concentration in both oils. In the presence of co-solvent, tetrahydrofuran (THF), methanolpis of mahua oil resulted in the increase of the rate constants from 0.08 to 1.17 L-2 mol(-2) min(-1) at 28 degrees C and from 0.43 to 3.18 L-2 mol min(-1) 45 degrees C. The corresponding values for jatropha oil were found to be 0.50 and 2.76 L-2 mol(-2) min(-1) at 28 degrees C and 1.26 and 4.56 L-2 mol(-2) min(-1) at 45 degrees C.