Knowledge and its intangible appurtenances have not only resulted in movement in various businesses, but also, nowadays, have been viewed as the whole or a part of products of distributors' companies as well as service and military organizations.In recent years, estimation of knowledge level in organizations and industry companies has attracted considerable attentions. Contrary to a lot of prevalent MODELs used for measuring efficiency, Data Envelopment Analysis (DEA) can take into account multiple inputs and outputs. In this regard, DEA was traditionally applied with crisp inputs and outputs, while in practical cases, we need to estimate organization efficiency in a different situation in which we have to deal with fuzzy or imprecise data. The aim of this paper is to present a DEA, employing fuzzy input and output data, toward assessing the knowledge levels established in a knowledge based-organization in various time intervals. In this case, the organization is able to define some areas in which it can improve its established knowledge level.