This study was carried out to investigate the presence of Listeria monocytogenes in samples obtained from a slaughterhouse in Samsun, Turkey. A total of 300 samples (25 samples per month) analyzed by Immunomagnetic Separation (IMS) based on conventional culture method. Then isolates were verified and serotyped by PCR using specific primers. According to the analysis, a total of 18 isolates were identified as L. monocytogenes Distribution of these isolates were as;5 isolates (serotype l/2b or 3b) from 1 cattle carcass, 5 isolates (serotype l/2b or 3b) from 1 knife, 2 isolates (serotype 4b or 4d, 4e) from 1 knife sharpener, 5 isolates (serotype l/2a or 3a) from 1 floor sample, 1 isolate (serotype l/2a or 3a) from 1 cowhide, respectively. As a result, carcasses are considered to pose a hazard to public health due to L. monocytogenes contamination. The development of slaughterhouse conditions and production technology, improving the education level of employees in food safety issues, prevention of contamination of foodborne pathogens to carcasses in slaughterhouses and implementation of effective sanitation methods should be provided.