The inhibition effects of sodium silicate, phytic acid and their mixtures in 5% NaCl solutions have been investigated using weight loss method and Tafel polarization techniques. The surface morphology of carbon steel was obtained using scanning electron microscopy (SEM). The results show that the co-addition of 70 mg∙1-1 sodium silicate and 5 g∙1-1 phytic acid has the optimum inhibition efficiency (84.15%) and the lowest corrosion rate (0.13 g∙m-2∙h-1). Compared with their individual inhibition effects, the optimum inhibition efficiency of sodium silicate is 62.17% at 90 mg∙1-1 and phytic acid is 80.05% at 15 g∙1-1, respectively. The results obtained from weight loss method and Tafel polarization curves are in good agreement. The results show the enhanced inhibition effect by the inhibitors mixtures.