Uncontrolled use of agricultural chemicals in intensive agricultural areas of Turkey causes serious soil, surface- and ground-water pollution. Controlled use of agricultural chemicals is of importance for preventing further pollution of these natural resources. The objectives of this paper are to present a screening model that can be used to determine the scientific criteria serving as basis of controlled pesticide use, to classify pesticides according to their pollution potential and, based on this classification, to determine the measures that can help regulate pesticide use in order to reduce groundwater pollution. Pesticide screening model (PESTRANS) considers basic physical chemical and biological transport processes and can describe the amount of pesticide mass that can potentially leach through soil to groundwater or beyond biologically active soil zone. Based on the results of PESTRANS simulations under standard soil and environmental conditions, pesticides are classified according to their volatilization, mobility and persistence characteristics and groundwater pollution potential. Classifications indicate that nearly 65% of the pesticides commonly used in Turkey has high pollution potential. In order to reduce the pollution potential of these pesticides, the current pesticide application rates must be reduced without significant loss of effectiveness or alternative pesticides having similar effectiveness with lower pollution potential must be used.