In this study, an optimized intermittent paddy rice dry- ing operation was investigated. A mathematical model composed of a lumped submodel (drying) and a distributed submodel (tempering) was developed. The model was vali- dated using experimental data. The design of the optimal conditions for the dryer was performed using the developed model. For the optimization problem, the process time was defined as the cost function and the drying rate was defined as the constraint. The optimization results showed that the first stage of drying was the longest, with a moderate tem- perature, and the next stages were shorter, with higher tem- peratures. Moreover, the optimizer took the defined constraints into account during all stages. The optimiza- tion problem herein implies that optimal control could be implemented for other drying processes with other appropriate cost functions and constraints.