Background: Identifying the animal species origin in meat and meat products is important for preventing adulteration and protecting consumers in terms of health and religious convictions. Species-specific polymerase chain reaction (PCR) is known as a suitable method for identifying meat species. OBJECTIVES: This study aimed to use a species-specific PCR assay for the detection of mislabeling in cooked sausage meats as adulterants by use of multiplex PCR. METHODS: A total of 114 samples including sausage labeled containing 40%, 55% and 70% red meat of 10 different brands were collected from various markets and supermarkets. Following genomic DNA extraction from cooked sausages which were claimed to be made of red meat, multiplex PCR was performed to detect adulteration in processed food.  RESULTS: According to the analysis, 60 sausage samples showed that they consist of only meat from chicken (52.6%), 48 sausage samples consist of meat from beef and chicken (42.1%) and only 5.3% of the examined sausages were prepared with the meat of beef (6 samples). CONCLUSIONS: This high rate of undeclared chicken meat in sausage samples is most probably due to achieving more profit. Our results indicated that the meat species substitution occurs often in processed meats like sausages, which indicates the need of more governmental controls.