Managing the inventories along with carrying out the production program is essential for many companies in the producing industry. In this paper, a fuzzy EPQ (Economic Production Quantity) model is developed to address this specific problem as a theoretical study. However, this problem derives from some real world applications, in which the producing company in a supply chain had to decide the size of the production batches under uncertainty. The uncertainty will be handled with fuzzy numbers and we will find an analytical solution to the optimization problem. The paper concludes with a small example to illustrate the analytical results.