The aim of the study was to develop and validate a real-time PCR method, using a TaqMan probe, for quantification of Mycoplasma suis in porcine blood. No PCR signals with closely related non-haemotrophic mycoplasmas were obtained. The detection limit of PCR for plasmid combined with blood DNA was determined to be 10³/reaction (5 µL of DNA) (1.2x10⁵ target copies in 1 mL of blood). The linearity of real-time PCR (near 1) indicates its use as a quantitative method. Real-time and quantitative PCR were sensitive and specific for the detection and quantification of M. suis in the blood of animals with acute and chronic form of eperythrozoonosis. Developed quantitative PCR cannot be used to detect carrier animals with a small amount of M. suis in their blood. The validity of real-time PCR used in the studies was confirmed by the low inter- and intra-assay coefficients of variation. This fact confirms the applicability of the assay in other laboratories.