The laboratory preparation procedure of a recently developed unsaturated polyester resin was followed to prepare the resin on a large scale (10- and 200-L pilot plant reactors). The process heating rate, reaction temperature, and agitator tip speed were kept constant on scale-up. The resin was successfully reproduced and its properties were unchanged upon scale-up. The effects of reaction temperature and inert gas flow rate on the polyesterification reaction rate were investigated. It was found that a 10°C increase in temperature or a 50% increase in the gas flow rate results in a 50% increase in the reaction rate.