本文主要探討需求與不良率兩者為模糊環境下，可立即退貨的經濟訂購批量(EOQ)模式。首先，本文建立在確定環境下，可立即退貨EOQ模式的利潤函数，並進一歩導出其最佳訂購量解；其次，再將利潤函數中的需求與不良率兩者模糊化，並用Yager的模糊數排序法，來求解該利潤函數的最佳訂購量解；最後，導出在需求與不良率兩者為三角模糊數的情況下，模式的利潤函數及其最佳訂購量解，並以25組的數值例子來說明該模式的特性與實務上的應用。

The purpose of the paper is to investigate an EOQ model with immediate return for imperfective items under the condition that fuzziness is introduced in both of demand and perfective rates. First, we construct the model in terms of annual profit and find the optimal order quantity with crisp case. Next, we develop the fuzzy inventory model by fuzzifying the demand and perfective rates, and utilize the Yager’s ranking method to determine the optimal order quantity. Third, we also provide an expression of the optimal order quantity for the case that both of the demand and perfective rates are triangular fuzzy numbers. Finally, based on 25 combinations of triangular fuzzy numbers of demand and perfective rates, a numerical example is provided to explore the features of the model.