Aims: The aim of the study was to assess the impact of Salmonella present on the slaughter line before processing on broiler carcass contamination during processing. Methods and Results: Three Belgian broiler slaughterhouses were each visited twice. Samples were taken from the slaughter line after the cleaning and the disinfection process and before slaughter of the first flock. During the slaughter of the first flock, feathers and neck skins were collected at various points of the slaughter process. Swab samples were also taken from the crates in which the birds were transported. In two slaughterhouses, the slaughter line was contaminated with Salmonella before the onset of slaughter, especially the shackles, conveyer belt and the plucking machine in the dirty zone. During slaughter, the carcasses of the first Salmonella-free flock became contaminated with the same strains as isolated previously from the slaughter line. Conclusion: Contamination of the slaughter line with Salmonella leads to carcass contamination. Significance and Impact of the Study: Implementation of logistic slaughter is only successful when the cleaning and disinfection process completely eliminates the Salmonella contamination of the slaughter line. Only if this is achieved, will the slaughter of Salmonella-free flocks result in the absence of Salmonella on the carcasses after slaughter.