Although traditional economic production quantity(EPQ) model assumes quality of produced items is perfect, this assumption of perfect quality is unrealistic in many industrial situations. As imperfect items in production process impact the inventory policy directly, this unrealistic assumption can lead to errors in determining the production lot size. Previously, several researchers has come up with a number of practical EPQ models when quality of produced items is imperfect. This paper deals with the situation where the items produced are a mixture of perfect and imperfect quality. Some of the imperfect items can be reworked and the others are scraped. We derive precise expressions for the expected profit per unit time and optimal production quantity when each production lot contains these two classes of imperfect quality. The analysis shows that our model is a generalization of the some models in current literatures. The implementation of the proposed model is shown using a numerical example. The sensitivity analysis is also performed to study the effect of imperfect rates of two classes on the optimal production quantity relative to traditional EPQ.