Effective and sustainable management of available water resurses has great importance by considering that the current increasing trend in world population and consequent decreasing trend in fresh water resources. It is possible to estimate the stresses on water resourses due to some factors such as current population growth ratio and variations of water consumption habits. This study is aimed to to develop climate dependent optimum dynamic management model of Lake Beyşehir which is one of the most important and yet the largest freshwater lake of Turkey. The concept of optimum dynamic model refers to determination of minimum allowable water surface elevation of lake management by using the precipitation, evaporation and groundwater elevation data of current and/or previous years. Optimization model is developed by using GAMS (General Algebraic Modeling System) software. Daily evapotranspiration is calculated by using Penman-Monteith method which is suggested by FAO (United Nations Food and Agriculture Organization). Crop-water requirement is calculated by Blaney-Criddle method which is widely used by aggricultural engineers. Groundwater levels are obtained from the regional groundwater flow model of the lake which was generated with MODFLOW software.