Abstract: In this study, Gene Expression Programming (GEP) is used to model evaporation using the meteorological data recorded from Automated GroWeather meteorological station near Lake Egirdir. Daily meteorological variables used in modeling are air temperature, solar radiation and relative humidity. Penman method daily evaporation estimations are used as output data for the verification of GEP approach. It is observed that GEP model is capable of yielding good model alternative with a high coefficient of determination and low mean square error as 0.95 and 0.125, respectively. It can be suggested that GEP approach is an alternative model of Penman method.