Abstract This research aimed to determine the physicochemical quality of beef sausages modified with transglutaminase enzymes (TGase) and external proteins. The physical properties of sausages include water holding capacity, cooking loss, pH, and tenderness. The chemical properties of sausages are water content, ash content, protein content and fat content. The treatment consisted of a control, namely the addition of STTP 0.3% (w/w), TGase 0.03% (w/w), TGase + skim milk 3.5% (w/w), TGase + SPI 3.5% (w/w), and TGase + WPI 3.5% (w/w). The results showed that the addition of transglutaminase enzyme or a combination with external protein significantly (P<0.05) improved the physical quality of sausages such as increasing water holding capacity and tenderness as well as reducing cooking losses and pH. The chemical quality of sausages also showed significant results (P<0.05), namely reducing water and fat content, and increasing ash and protein content in sausages. Comparison between TGase + SPI and TGase + WPC did not show significantly different results. The conclusion of this research is that the physicochemical properties of beef sausage can be modified using the TGase enzyme, but it would be better if TGase was combined with an external protein.