This paper surveyed rice farmers 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 first area is Dai Tam village completely unaffected by salt water intrusion at the period from the end of 2015 to the beginning of 2016, the most heavily salinity-affected time in the Vietnamese Mekong Delta. Two other areas were Lieu Tu and Lich Hoi Thuong village rated as high and very high salinity respectively. The results showed that rice yield loss due to saltwater intrusion was estimated from 2.5 to 4.05 tons ha-1 a year.