A survey was conducted on 4,656 pigs in household sector having swine blue ear disease (PRRS) in Ben Tre province from Aug. to Oct. 2010 to determine the epidemiology characteristics of the disease. The results showed: - The morbidity in a herd was 80.4 percent [79.3 -81.6 percent] and the mortality was 6.6 percent [5.9-7.3 percent]. - The specific morbidity was 72.2 percent [68.8 - 75.5] in the sows, 5.0 percent [4.2 - 6.0] in the finishers and 69.2 percent [66.9 - 71.5] in the piglets. - The incidence of the disease was 0.09 pig per day. - The disease occurred mainly in herds of less than 40 heads (78 percent), the herd morbidity decreased inversely as a function of the head number of the herd. So the morbidity of herds of 80 to 100 heads was 1.9 and 2.5 percent.