The aim of this work was to establish the effect of gamma irradiation on the viscoelastic properties of the sodium alginate. Aqueous suspensions of sodium alginate at different concentrations (0.25 – 4%) were irradiated using a 60 Co gamma-ray source (10, 25 and 50 kGy). The monitored rheological parameters showed the non-Newtonian behavior of the samples is kept by gamma irradiation. The decrease tendency of the apparent viscosity by irradiation samples and with decrease of the concentration as well has been noticed.