This research investigated variation in the improvement of the texture of chicken and pork sausages induced by microbial transglutaminase (MTG). The extractability of myofibrillar proteins from these sausages as well as the epsilon-(gamma-glutamyl)lysine (G-L) content were also investigated. MTG treatment of sausages significantly increased the breaking strength values in both meat types, especially for samples incubated at 40 degrees C. However, values of the breaking strength in both meat types were increased differently. The variation in protein extractability of samples incubated at 40 degrees C for both meat types could lead to some consideration of the mechanisms and the high accessions of myosin heavy chain (MHC) to MTG SDS-PAGE analysis showed significant changes in the density of the bands after adding MTG, especially for the pork samples in which the bands disappeared totally. The G-L content in the presence of MTG was double that in control samples of both meat types. This study suggests that the binding ability of myofibrillar proteins with MTG is strong. This leads us to suggest that MTG functions positively with different improvements in the texture of chicken and pork products that are treated mechanically, such as sausages. Variability in gel improvement level between chicken and pork sausages was observed; this resulted from the variation in meat proteins in response to MTG as well as to the original glutamyl and lysine content.