This study deals with evaluating the performance of an olive oil refinery plant installed in Izmir, Turkey, using Exergy, Cost, Energy and Mass (EXCEM) method, which is based on the real operational data and costs of the equipments. The most efficient equipment is obtained to be the shell and tube type heat exchanger with an exergy efficiency value of 85.8% at 25°C, ranging from 86.2% to 85% for dead-state temperatures ranging from 10°C to 30°C. The functional exergetic efficiency of the whole plant is found to be about 16%, changing between 21.3 and 14.3%. The exergy efficiency value for the whole system on the exergetic fuel-product basis is calculated to be 67.5%.