Most developed countries have environmental policies that promote the development and application of renewable energies, and among these is biodiesel. However, the optimization of the chemical reaction that is required to produce biodiesel, called transesterification, is a costly and time-consuming process that needs expensive reactants and laboratory equipment. In this context, an artificial neural network (ANN) model has been developed to simulate biodiesel production through the transesterification of used frying olive oil. Afterward, the model was validated with sets of experimental data obtained from the laboratory and that were not used during the training procedure. In this sense, simulated results were similar to those obtained with the help of the classical empirical tests required to perform the transesterification process in a laboratory, thus, indicating the simulated biodiesel yield function has properly reflected the real process. We can conclude that ANNs can be used to predict the biodiesel yield from used olive oil.