Background and objective: The identification of animal-derived ingredients in a vegetarian product is an important issue to protect the consumer from undesirable adulteration, especially, for religious and health reasons. Therefore, it is necessary to establish a rapid method for detecting meat ingredients in processed vegetarian foods. Materials and methods: The multiplex PCR assay, based on the amplification of mitochondria cytochrome b gene, specific to most of the animals, and chloroplast DNA, specific to plant species and served as internal control, were established. Experimentally, a total of 200 vegetarian samples, collected from local markets, were enrolled in the current study. Results and Conclusion: 68/200 (counting for 34.0%) samples were positive, which meant having animal-derived ingredients in their foods processing. Also, representative PCR products were conducted sequencing, that showed the animal-derived ingredients. In summary, the results indicated the multiplex PCR could be a reliable method to detect animal-derived ingredients in vegetarian foods applied on a large number of samples in the reality. Conflict of interest: The authors declare no conflict of interest.