This study aims to understand the infection status of Plasmodium knowlesi and Babesia microti in farmed monkeys in Guangxi to assess its risk as reservoir host for human infections. Total 600 blood samples were collected from monkeys raised in a farm in Guangxi including 330 Macaca fascicularis and 270 M. mulatta. The infections of B. microti and P. knowlesi were detected by amplifying 18S rRNA of each species using nested PCR. The PCR products of positive samples were DNA sequenced, and then BLAST searched to confirm the species of infected parasite. The nested PCR results showed that 16 monkeys were infected with B. microti with overall positive rate of 2.7% （16/600）. These infected monkeys included 13 Macaca fascicularis and 3 Macaca mulatta with infection rates of 3.9% (13/330) and 1.1% (3/270), respectively. The difference of B. microti infection between these two monkey species was statistically significant (P < 0.05). Four PCR products were sequenced and the obtained sequences possessed 99.9% sequence identity to B. microti (GenBank accession number: KC904078.1). No infection of P. knowlesi was detected in the examined 600 monkey blood samples. The results suggested that infection of B. microti was detectable in the farmed moneys which could be the potential reservoir host for human Babesia infection in Guangxi, while infection of P. knowlesi was not identified in these farmed monkeys.