To fulfil the consumer demands about food safety, quality control systems are necessary in the entire food production chain, including pig production. One of the tools to control quality is a HACCP-system, based on control points. The aim of present study was to define control points in 12 closed pig herds based on slaughterhouse data. Herd data, obtained by questionnaires, comprised data about housing and ventilation, management, feeding, hygiene, prevention of diseases and transport to the slaughterhouse. Outcome variables for the univariate analysis were the percentage of animals with lung lesions, pleuritis, dermatitis scores, white spots on the liver and the Salmonella prevalence. The results of this study should be interpreted with caution, since the analysis was carried out on no more than 12 herds and because no multivariate analysis was done. However, it is clear that slaughterhouse data are essential for the farmer to optimize the production of healthy and safe pigs.