Methyl esters were produced by trans-esterification of c ottonseed oil with methanol in the presence of a homogeneous catalyst (KOH).A ki netic model was established by taking three consecutive and reversible reactions into consideration.Rate constants were determined for each reaction by the Rung e-Kutta method with optimization.The corresponding values of frequency factor a nd activation energy were then obtained based on the Arrhenius’ law for a ll forward and reverse reactions under different experimental conditions.