The corrosion behavior of pure magnesium in sodium sulfate solution was studied to establish a baseline understanding for magnesium alloy corrosion in different pH environments. Electrochemical techniques such as potentiodynamic polarization measurements, electrochemical impedance spectroscopy (EIS) and weight loss methods were compared. SEM examinations were conducted on the corroded surface and the cross-section to characterize the corrosion product and to observe the evolution of corrosion process. A six-element equivalent circuit model was used to describe active and passive corrosion behavior of magnesium in 1N sodium sulfate solution at different pH values. Due to the formation of a stable corrosion film, the corrosion current (icorr) at pH 13 was two orders of magnitude lower than at pH 8. Immersion corrosion tests showed that the weight loss at pH 8 increased linearly with time. However, for pH 12 and 13 solutions, the corrosion stopped once the passive film was formed. The importance of corrosion test duration is also described in this paper.