The postweaning multisystemic wasting syndrome (PMWS) in piglets was identified by autopsy in 110 out of 170 (64.71 percent) culled piglets from 82 swine farms in 2 provinces in Southeast Vietnam. The main lesions were the swollen lymph nodes, especially the mesenteric and the inguinal ones. The microscopic lesions consisted of the disappearance of the lymph tissue and infiltration of the macrophages in the following lymph nodes: inguinal (100 percent, 18.18 percent), mesenteric (72.73 percent, 10.91 percent), spleen (25.45 percent, 4.54 percent) pulmonary (9.09 percent, 0 percent, respectively). The secondary bacterial infection was found in the lymph node of 40 PMWS and 20 non-PMWS piglets. In the PMWS piglets, the infection by E. coli was found highest (55 percent), followed by Streptococcus (42.5 percent), Salmonella (32.5 percent), Pasteurella multocida (22.5 percent) and Haemophilus parasuis (17.5 percent). The triple co-infection was found only in the PMWS piglets (20 percent).