Result of analysing 26 PRRS virus positive pig specimens indicated that there-was the presence of many other pathogens including Pasteurella multocida (65.38 percent), Porcine circovirus type 2 (38.46 percent), Haemophilus parasuis (34.61 percent), Actinobacillus pleuropneumoniae (30.76 percent) and Hog cholera virus (11.35 percent), whereas no Streptococcus suis type 2 was detected in the tested samples. This study result also showed the high mortality rate of pig in the PRRS outbreaks in Can Tho in the period 2011-2012 might be due to the effect of some bacteria and viruses caused concurrent infections and/or superinfections. Using recommended antibiotics as an effective measure against these isolated bacteria to interfere in PRRS outbreaks could significantly reduce the mortality rate in pigs having clinical signs of PRRS. Of which, procedure of using tulathromycine in combination with ceftiofur may increase the recovery of the PRRS infected pigs up to 87 percent.