In this study, exergy of diffuse solar radiation is estimated using empirical models. Long-term meteorological data (1983-2005) consisting of monthly mean diffuse solar radiation for seven selected stations were available from NASA Langley Research Centre. Empirical models were developed by correlating diffuse solar radiation exergy in terms of relative sunshine period. The performance ranking of the models is carried out by using the global performance indicator (GPI) method. The maximum diffuse solar radiation exergy value (53 MJ/m(2) year) belongs to Adana for selected provinces. Quadratic type is the best predictive method for Bursa, Ankara, Adana, Gaziantep provinces located in Turkey, and Igdir and Trabzon regions are excellently predicted by cubic type. Linear type is then used for the best prediction of the Izmir city of Turkey. Consequently, the empirical models obtained in this study can successfully predict diffuse solar radiation exergy.