The absence of a concrete method for economic analysis is one of the main reasons that the RFID is not so widespread. Through literature survey and a case study of a courier service company we propose a novel method of economic justification including cost and benefit analysis. In order to reflect the uncertainties caused by the RFID technology itself and the estimated investment cost, we propose optimistic, conservative and pessimistic estimations of benefits and a sensitivity analysis of investment costs. This paper may contribute the systematic evaluation of cost and benefit of RFID adoption.