The evolution of monitoring and surveillance for bovine spongiform encephalopathy (BSE) from the phase of passive surveillance that began in the United Kingdom in 1988 until the present is described. Currently, surveillance for BSE in Europe consists of mass testing of cattle slaughtered for human consumption and cattle from certain groups considered to be at higher risk of having clinical or detectable BSE. The results of the ongoing BSE testing in Denmark have been analyzed using two statistical approaches: the "classical" frequentist and the Bayesian that is widely used in quantitative risk analysis. The analyses were intended to provide information for decision-makers, the media and the public as well as to provide inputs for future BSE surveillance models. The results to date suggest that the total number of BSE cases that will be found in Denmark in 2001 will not exceed 16.