Mycoplasma bovis and Mycoplasma mycoides subspecies mycoides small colony (MmmSC) are causes of bovine mycoplasmosis and contagious bovine pleuropneumonia (CBPP), respectively, and are responsible for serious economic losses in cattle around the world. CBPP was last reported in Poland in 1939 but bovine mycoplasmosis is believed to be endemic. A survey of 3670 serum samples for antibodies to M bovis and MmmSC from 361 herds in 16 Polish provinces Poland between 2007 and 2010 found no evidence of CBPP. The seroprevalence of M bovis, however, appeared high with 76.7 per cent of samples giving a positive reaction in the ELISA test, which did not appear to reflect the clinical disease status of the cattle. Adjusting the sensitivity of the test reduced the prevalence to 28.2 per cent and reflects the levels reported in other European countries.