Waste fish oil, palm oil and waste frying oil were used to produce biodiesel. A simplex centroid design with 16 experiments was carried out. It comprised 16 different oil contents as biodiesel feedstock, including pure oils and mixtures of two and three oils in different ratios. The content in free fatty acids (FFA) of the three oils was higher than 2 mg KOH/g oil, what impairs the biodiesel production