Rheological properties and microstructure of beef meat sausage batter, incorporated with different percentages of fish fillet mince (5 %, 20 %, 35 % and 50 %), were investigated and compared to the control (0 % fish). By increasing the proportion of fish fillet mince to the sausage formula up to 35 % and 50 %, hardness was increased by 40 % and 16 %, respectively, (P < 0.05), whereas, cohesiveness and springiness showed no significant differences (P > 0.05). In terms of temperature sweep test, storage modulus (G′) of control sample faced a substantial slop from 10°C to 58°C, corresponding to the lowest magnitude of G′ at its gelling point (~58°), but completed at around 70°C, as same as the other treatments. Whereas the gelling point of batter sample with 50 % fish mince remained at nearly 42°C, which was remarkably lowest among all treatments, indicating the better gel formation process. SEM micrographs revealed a previous orderly set gel before heating in all treatments whereas after heating up to 90°C gel matrices became denser with more obvious granular pattern and aggregated structure, specifically in sample with 50 % fish mince. In conclusion, addition of fish mince up to 50 % into beef sausage formula, positively interacted in gel formation process, without diminishing its rheological properties.