Nowadays, the consumption of meat and meat products has been increased with modern manufacturing techniques. Due to the economic value, the likelihood of using unauthorized tissue is possible in meat products. The aim of this study was to apply morphological methods for detection of unauthorized tissues in meat SAUSAGE. In this study, a total number of 20 samples of different types of SAUSAGEs were randomly collected from markets, in north-east of Iran. Each sample was divided into three equal parts and three paraffin-embedded blocks were prepared from each part (180 blocks). Then the sections were stained using Hematoxylin and Eosin, Masson’ s trichrome, Periodic acid-Schiff/Alcian blue and Verhoeffe/Van Gieson. A total number of 720 slides were observed using a light microscope. This research showed the use of unauthorized tissues in the SAUSAGEs which was detected by histological methods. We observed authorized tissues like skeletal muscle fiber (100%), fat tissue (100%) and plant material (97. 70%). A wide range of unauthorized tissues were detected including dense connective tissue (6. 66%), cartilage (28. 30%), bone (8. 30%), skin (51. 60%), smooth muscle (1. 66%) and blood vessels (11. 66%). The results of this study confirmed the use of unauthorized tissue in meat SAUSAGEs in Iran and concluded that the histological methods especially Masson’ s trichrome staining are a practical technique for routine assessment of authenticity and quality of SAUSAGE to protect the consumers from adulteration.