The global energy demand is increasing day by day. Fossil fuels such as crude oil, coal and gas are the main source of energy worldwide. However, fossil fuels, which cause acid rain, the greenhouse effect and other such environmental problems, will eventually be depleted, and renewable energy seems to be the most reasonable solution in this regard. Renewable biofuels have significant potential and can meet the world’s current energy demand. One of the important biofuels is biodiesel, and in the future it can replace petroleum. Waste cooking oil was used as a raw material in biodiesel production in order to reduce the production cost of the offered additive. In this study, the aim was to optimize the process parameters for biodiesel production within the acceptable limit values in the literature. Therefore, the molar ratio of methanol to waste cooking oil (9:1−15:1), catalyst concentration (1−5% by weight) and reaction time (60−120 min) were studied for two catalyst types, potassium hydroxide and ion exchange resin Amberlyst 15. The biodiesel obtained with maximum efficiency for each catalyst was also compared with the international biodiesel standards.