Mycoplasma (M.) hyopneumoniae is the causative agent of swine enzootic pneumonia, a disease that is prevalent in every country where pigs are raised. In this study, we aimed to develop a sensitive and specific PCR assay to detect M. hyopneumoniae in pigs. The suitability of this PCR assay for the detection of mycoplasmal infection was also tested using clinical lung samples from slaughtered pigs. We de- veloped a probe and M. hyopneumoniae-specific primer pairs, MhyoP-F and MhyoP-R, for the new PCR assay based on regions in the Mycoplasma protein P97 gene that are unique to M. hyopneumoniae. The developed PCR as- say was very specific and sensitive for the detection of M. hyopneumoniae. The assay was able to detect the equivalent of 10 pg of target template DNA, which indicates that the assay was very sensitive. In addition, the M. hyopneumoniae PCR assay detected only M. hyopneumoniae and no other Mycoplasma spp. or bacterial species of another genera. Further, the newly developed PCR assay effectively detected M. hyopneumoniae infection in pigs. We suggest that this PCR assay using M. hyopneumoniae-specific primer pairs, MhyoP-F and MhyoP-R, will be useful and effective for monitoring M. hyopneumoniae infection in pigs.