Cold-set gels of whey protein isolate (WPI) and of WPI plus polysaccharide were produced. The cold gelation was induced through the addition of magnesium chloride whose cation is an alternative to the most common cations used in this kind of gelation. The polysaccharide used was tara gum (TG) which is a galactomannan with many applications in the food industry. The viscoelastic behaviour of the WPI, TG and WPI+TG samples was analysed: Newtonian behaviour was observed for WPI while TG and WPI+TG displayed typical rheological behaviours of thickened fluids that can be described through the Cross and Carreau models, for which the parameters are presented.