This chapter illustrates the relationship between investment in irrigation infrastructure and other agricultural policies and their impacts on rice production. Other agricultural policies must complement the irrigation investment in order to obtain positive production increases. Disaggregated data which differentiates between wet and dry season rice production offer new insights into the process of agricultural development. Rice is Thailand's leading earner of foreign exchange while the rice export premium provides an important source of government revenue. Major policy variables influencing rice production in Thailand are rice price, fertilizer price, land tenure, and irrigation development. The principal rice policy objective of government of Thailand is to control the volume of rice exports in order to make certain that domestic supplies are adequate to maintain a desired Bangkok consumer price level for rice. Crop production in any agricultural system requires management of the factors of production to increase yield.