The chapter aims to evaluate the profit loss of rice farmers due to salinity intrusion by collecting the information of rice production in three regions with the same natural environment conditions, social characteristics (e.g., the same social and farming culture, ethnicity, type of soil), and only differed with respect to the level of salinity in Soc Trang province, one of the most salinity-affected areas in the Vietnamese Mekong Delta. The study estimated the profit loss in rice production due to saltwater intrusion by the difference in rice profit between the non-salinity and salinity regions and showed this loss was about VND 9.3-15.1 million per ha-1 a year.