The prevalence of hemotropic mycoplasmas in wild monkeys is largely unknown. Here, we report the presence of hemoplasmas in blood specimens collected from wild Japanese monkeys (Macaca fuscata) tentatively captured for ecological survey in Mie prefecture, Japan. We examined 9 monkeys using hemoplasma-specific real-time PCR and found all of them positive for a hemoplasma infection. The 16S rRNA gene and 16S to 23S rRNA intergenic spacer region of the hemoplasma detected in wild monkeys were amplified using end-point PCR. The nucleotide sequences of the PCR products were further determined and compared to those of other hemoplasmas. Our examinations revealed a wide prevalence of a hemoplasma strain in Japanese monkeys, which was similar to 'Candidatus Mycoplasma haemomacaque' reported in cynomolgus monkeys (Macaca fascicularis). Pathogenic traits of this hemoplasma strain remain unexplored.