A multiplex seminested polymerase chain reaction (PCR) was developed for the simultaneous detection and differentiation among porcine circovirus 1 (PCV1), PCV2, and porcine parvovirus (PPV) from boar semen. Primers of PCV1, PCV2 and PPV were specific and did not react with other viruses respectively. Twenty (20.4%) and 42 (42.9%) out of 98 whole semen samples were found to be positive for PCV and PPV using multiplex conventional and seminested PCR, respectively. When the separated fractions of PCV or PPV-contaminated semen were analyzed using multiplex seminested PCR, PCV and PPV DNA were found to be present mainly in the seminal fluid and nonsperm cell fractions. This multiplex seminested PCR assay was sensitive, rapid and a good alternative method for the detection and differentiation of these viruses in boar semen.