► During the production of cement it is necessary to add a reducing agent to convert Cr VI into Cr III. ► This paper explores effects of iron(II) sulphate on corrosion of steel reinforcement. ► Accelerated corrosion testing in pore solutions was performed. ► Results indicate that iron(II) sulphate may foster or accelerate steel corrosion. ► Further research is needed on steel corrosion in concrete environments. During the production of cement it is necessary to add a reducing agent that converts soluble hexavalent chromium into trivalent chromium. This paper explores effects of iron(II) sulphate reducing agents, namely monosulphate and heptahydrate, as cement admixtures, on corrosion of concrete reinforcement. Accelerated corrosion tests of reinforcing steel have been performed in pore solutions simulating concrete prepared using either CEM I or CEM II type cement, with addition of various concentrations of iron(II) sulphate reducing agent. All of the test results indicate corresponding tendencies and point towards the potential for iron(II) sulphate to foster or accelerate corrosion of the reinforcement. The results of this study indicate an immediate need for a more detailed research, especially in concrete as a more realistic corrosion environment, of the application of iron(II) sulphate as a reducing agent in cement.