Engineering economics is an essential issue in investments and can be quietly difficult to make decisions especially in indefinite, vague and incomplete environments because of human thought. Usage of fuzzy sets gives better solutions in vagueness. Fuzzy sets could be an agreeable tool when no probabilities are accessible for states of nature and decisions are given under incompleteness. In this study, fuzzy engineering economics studies are summarized for showing fuzzy sets usage in engineering economics applications and finding gaps for future studies. The possible suggested are given in conclusion.