Livestock producers in developed countries, such as pig producers, are facing the challenge to produce high quality products which satisfy their customers. Quality assurance programmes therefore are likely to become more important in the near future (Blaha, 1997). A prerequisite to the development of such programmes is the knowledge of animal health data, including zoonoses. In this context, an epidemiological study of the pig health and productivity in Switzerland, called "Schwein 99", has been initiated. This study has the overall objective to study the health and production profile of swine in a broad approach, where pigs are expected to be followed from birth to slaughter. Thus it will be carried out at three levels, i.e. at the breeding units, the fattening units and the abattoirs, respectively. This paper presents preliminary results from a pilot study carried out prior to the larger project to investigate the importance of selected zoonoses, Salmonella, Yersinia enterocolilica and Mycobacterium avium, in slaughtered healthy pigs.