Complex coacervation is a liquid-liquid phase separation that occurs between two oppositely charged macromolecules and leads to the formation of a concentrated phase called coacervates. Coacervates are proposed as efficient encapsulating agents for bioactives. Here, we studied the specific case of heteroprotein complex coacervation (HPCC) between positively charged Lactoferrin (LF) and negatively charged β-lactoglobulin (β-LG). We investigated the effects of ionic strength and temperature on the rheological properties of LF/β-LG coacervates. The maximum coacervation yield was reached at 20 °C and without added salt. In these conditions, the heteroprotein coacervates exhibits a Newtonian viscous flow under low shear rate and a shear thinning behavior above 10 s-1 with a hysteresis loop between the upward and downward flows. The addition of a small amount of NaCl (5 mM) had no effect on the viscosity of the coacervate. However, no phase separation was observed at 20 mM of salt due to a large reduction of electrostatic interactions between the two proteins. The increase of the temperature from 20 °C to 40 °C caused an outstanding decrease of the viscosity value of the Newtonian plateau from 60 Pa.s to 8 Pa.s with an almost complete loss of the hysteresis loop at 40 °C. In addition, β-LG/LF heteroprotein coacervates exhibit a liquid-like behavior regardless of the ionic strength and the temperature studied. However, in a rather unexpected way, the loss tangent value was lower at 40°C than at 20°C especially at low frequencies. These results allow better understanding of the involved interactions in concentrated protein solutions and open new avenues for the use of coacervates as texturizing agents in food matrices.