This paper deals with the performance evaluation of a single layer drying process of green olives in a tray dryer using exergy analysis method. Green olive was used as the test material being dried. Drying process was realized at four different drying air temperatures (40, 50, 60 and 70 degrees C) and a constant relative humidity of 15%. The effects of temperatures and mass flow rates were investigated. Maximum exergy efficiency of the drying chamber was obtained at a temperature of 70 degrees C and a drying air mass flow rate of 0.015 kg/s with 0.0004 kg/s of olive. The exergy efficiency values were found to be in the range of 68.65%-91.79% from 40 degrees C to 70 degrees C with drying air mass flow rates of 0.01 kg/s-0.015 kg/s. (c) 2006 Elsevier Ltd. All rights reserved.