Peccaries and pigs, Tayassuidae and Suidae respectively, diverged approximately one million years ago from a common ancestor. Because these families share some pathogens, peccaries can act as reservoirs of infectious pathogens for domestic and wild swine. We evaluated the presence of swine infectious agents in the spleen and lung tissues of white-lipped peccaries (WLP; Tayassu pecari) and collared peccaries (CP; Pecari tajacu) in Brazil. Samples from 10 adult CP and three WLP, which had been hunted by locals or hit by motor vehicles, were obtained from two free-ranging Brazilian populations. The samples were tested by PCR for Mycoplasma hyopneumoniae, Bordetella bronchiseptica, Pasteurella multocida, porcine circovirus 2 (PCV2), Suid herpesvirus 1 (SuHV-1), and porcine parvovirus (PPV). Positive samples were sequenced. Both species were negative for PPV and B. bronchiseptica and positive for PCV2 and SuHV-1. The lungs of two animals were positive for M. hyopneumoniae and P. multocida. This report is the first demonstration of PCV2 and SuHV-1 swine viruses and of M. hyopneumoniae and P. multocida bacteria in peccaries. One factor contributing to this detection was access to tissue samples, which is uncommon. The role of these infectious agents in peccaries is unknown and further epidemiologic studies should be performed. This study identified several infectious agents in peccaries and highlighted the importance of the tissue type used to detect pathogens.